[{"data":1,"prerenderedAt":3594},["ShallowReactive",2],{"item-lessons-light-ch24-optional-avoiding-null-pointer-exceptions":3,"item-examples-light-ch24-optional-avoiding-null-pointer-exceptions":444,"item-exercises-light-ch24-optional-avoiding-null-pointer-exceptions":753,"item-lesson-full-ch24-optional-avoiding-null-pointer-exceptions-24":1070,"item-example-full-ch24-optional-avoiding-null-pointer-exceptions-24":1711,"item-exercise-full-ch24-optional-avoiding-null-pointer-exceptions-24":2327},[4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92,96,100,104,108,112,116,120,124,128,132,136,140,144,148,152,156,160,164,168,172,176,180,184,188,192,196,200,204,208,212,216,220,224,228,232,236,240,244,248,252,256,260,264,268,272,276,280,284,288,292,296,300,304,308,312,316,320,324,328,332,336,340,344,348,352,356,360,364,368,372,376,380,384,388,392,396,400,404,408,412,416,420,424,428,432,436,440],{"path":5,"title":6,"stem":7},"\u002Fshockwave-curriculum\u002Flessons\u002Fch01-why-java-for-frc\u002F1-why-java-for-frc","Why Java for FRC?","shockwave-curriculum\u002Flessons\u002Fch01-why-java-for-frc\u002F1.1-why-java-for-frc",{"path":9,"title":10,"stem":11},"\u002Fshockwave-curriculum\u002Flessons\u002Fch01-why-java-for-frc\u002F2-intro-to-algorithms-programming-and-compilers","Intro to Algorithms, Programming and Compilers","shockwave-curriculum\u002Flessons\u002Fch01-why-java-for-frc\u002F1.2-intro-to-algorithms-programming-and-compilers",{"path":13,"title":14,"stem":15},"\u002Fshockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F1-variables-and-data-types","Variables & Data Types","shockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2.1-variables-and-data-types",{"path":17,"title":18,"stem":19},"\u002Fshockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2-expressions-and-output","Expressions & Output","shockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2.2-expressions-and-output",{"path":21,"title":22,"stem":23},"\u002Fshockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F3-assignment-and-input","Assignment & Input","shockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2.3-assignment-and-input",{"path":25,"title":26,"stem":27},"\u002Fshockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F4-casting-and-ranges-of-values","Casting & Ranges of Values","shockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2.4-casting-and-ranges-of-values",{"path":29,"title":30,"stem":31},"\u002Fshockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F5-compound-assignment-operators","Compound Assignment Operators","shockwave-curriculum\u002Flessons\u002Fch02-variables-and-types\u002F2.5-compound-assignment-operators",{"path":33,"title":34,"stem":35},"\u002Fshockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F1-apis-and-libraries","APIs and Libraries","shockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F3.1-apis-and-libraries",{"path":37,"title":38,"stem":39},"\u002Fshockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F2-documentation-with-comments-and-preconditions","Documentation with Comments and Preconditions","shockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F3.2-documentation-with-comments-and-preconditions",{"path":41,"title":42,"stem":43},"\u002Fshockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F3-packages-and-imports","Packages & Imports","shockwave-curriculum\u002Flessons\u002Fch03-apis-libraries-and-documentation\u002F3.3-packages-and-imports",{"path":45,"title":46,"stem":47},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F1-methods-signatures-and-parameters","Methods, Signatures & Parameters","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.1-methods-signatures-and-parameters",{"path":49,"title":50,"stem":51},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F2-calling-class-methods","Calling Class Methods","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.2-calling-class-methods",{"path":53,"title":54,"stem":55},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F3-using-the-math-class","Using the Math Class","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.3-using-the-math-class",{"path":57,"title":58,"stem":59},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4-objects-instances-of-classes","Objects — Instances of Classes","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.4-objects-instances-of-classes",{"path":61,"title":62,"stem":63},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F5-creating-and-initializing-objects-constructors","Creating & Initializing Objects: Constructors","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.5-creating-and-initializing-objects-constructors",{"path":65,"title":66,"stem":67},"\u002Fshockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F6-calling-instance-methods","Calling Instance Methods","shockwave-curriculum\u002Flessons\u002Fch04-using-objects-and-calling-methods\u002F4.6-calling-instance-methods",{"path":69,"title":70,"stem":71},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F1-5.2-if-statements-and-for-loops","Control Structures: if Statements & For Loops","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.1-5.2-if-statements-and-for-loops",{"path":73,"title":74,"stem":75},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F10-nested-iteration","Nested Iteration","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.10-nested-iteration",{"path":77,"title":78,"stem":79},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F11-informal-runtime-analysis-of-loops","Informal Runtime Analysis of Loops","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.11-informal-runtime-analysis-of-loops",{"path":81,"title":82,"stem":83},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F12-switch-statements-and-expressions","switch Statements and Expressions","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.12-switch-statements-and-expressions",{"path":85,"title":86,"stem":87},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F3-algorithms-with-selection-and-repetition","Algorithms with Selection and Repetition","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.3-algorithms-with-selection-and-repetition",{"path":89,"title":90,"stem":91},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F4-boolean-expressions","Boolean Expressions","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.4-boolean-expressions",{"path":93,"title":94,"stem":95},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5-nested-if-statements","Nested if Statements","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.5-nested-if-statements",{"path":97,"title":98,"stem":99},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F6-compound-boolean-expressions","Compound Boolean Expressions","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.6-compound-boolean-expressions",{"path":101,"title":102,"stem":103},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F7-comparing-boolean-expressions-de-morgans-laws","Comparing Boolean Expressions (De Morgan's Laws)","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.7-comparing-boolean-expressions-de-morgans-laws",{"path":105,"title":106,"stem":107},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F8-while-loops","While Loops","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.8-while-loops",{"path":109,"title":110,"stem":111},"\u002Fshockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F9-implementing-selection-and-iteration-algorithms","Implementing Selection and Iteration Algorithms","shockwave-curriculum\u002Flessons\u002Fch05-control-structures\u002F5.9-implementing-selection-and-iteration-algorithms",{"path":113,"title":114,"stem":115},"\u002Fshockwave-curriculum\u002Flessons\u002Fch06-strings\u002F1-strings","Strings","shockwave-curriculum\u002Flessons\u002Fch06-strings\u002F6.1-strings",{"path":117,"title":118,"stem":119},"\u002Fshockwave-curriculum\u002Flessons\u002Fch06-strings\u002F2-string-algorithms","String Algorithms","shockwave-curriculum\u002Flessons\u002Fch06-strings\u002F6.2-string-algorithms",{"path":121,"title":122,"stem":123},"\u002Fshockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F1-anatomy-of-a-java-class","The Class Blueprint","shockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F7.1-anatomy-of-a-java-class",{"path":125,"title":126,"stem":127},"\u002Fshockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F2-methods-how-to-write-them","Methods: How to Write Them","shockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F7.2-methods-how-to-write-them",{"path":129,"title":130,"stem":131},"\u002Fshockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F3-methods-passing-and-returning-references-of-an-object","Methods: Passing & Returning References of an Object","shockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F7.3-methods-passing-and-returning-references-of-an-object",{"path":133,"title":134,"stem":135},"\u002Fshockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F4-class-static-variables-and-methods","Class (static) Variables & Methods","shockwave-curriculum\u002Flessons\u002Fch07-the-class-blueprint\u002F7.4-class-static-variables-and-methods",{"path":137,"title":138,"stem":139},"\u002Fshockwave-curriculum\u002Flessons\u002Fch08-constructors-and-this\u002F1-8.2-constructors-and-this","Constructors & \"this\"","shockwave-curriculum\u002Flessons\u002Fch08-constructors-and-this\u002F8.1-8.2-constructors-and-this",{"path":141,"title":142,"stem":143},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F1-array-creation-and-access","Array Creation and Access","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.1-array-creation-and-access",{"path":145,"title":146,"stem":147},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F2-arraylist-and-its-methods","ArrayList and its Methods","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.2-arraylist-and-its-methods",{"path":149,"title":150,"stem":151},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F3-optional-hashmap-dictionary-data-structure","HashMap (Dictionary) Data Structure","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.3-optional-hashmap-dictionary-data-structure",{"path":153,"title":154,"stem":155},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F4-array-traversals","Array Traversals","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.4-array-traversals",{"path":157,"title":158,"stem":159},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F5-implementing-array-algorithms","Implementing Array Algorithms","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.5-implementing-array-algorithms",{"path":161,"title":162,"stem":163},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F6-arraylist-traversals","ArrayList Traversals","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.6-arraylist-traversals",{"path":165,"title":166,"stem":167},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F7-implementing-arraylist-algorithms","Implementing ArrayList Algorithms","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.7-implementing-arraylist-algorithms",{"path":169,"title":170,"stem":171},"\u002Fshockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F8-using-text-files","Using Text Files","shockwave-curriculum\u002Flessons\u002Fch09-storing-data\u002F9.8-using-text-files",{"path":173,"title":174,"stem":175},"\u002Fshockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F1-2d-array-creation-and-access","2D Array Creation and Access","shockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F10.1-2d-array-creation-and-access",{"path":177,"title":178,"stem":179},"\u002Fshockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F2-2d-array-traversals-nested-loops","2D Array Traversals: Nested Loops","shockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F10.2-2d-array-traversals-nested-loops",{"path":181,"title":182,"stem":183},"\u002Fshockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F3-implementing-2d-array-algorithms","Implementing 2D Array Algorithms","shockwave-curriculum\u002Flessons\u002Fch10-2d-arrays\u002F10.3-implementing-2d-array-algorithms",{"path":185,"title":186,"stem":187},"\u002Fshockwave-curriculum\u002Flessons\u002Fch11-enums-named-choices\u002F11-enums-named-choices","Enums: Named Choices","shockwave-curriculum\u002Flessons\u002Fch11-enums-named-choices\u002F11-enums-named-choices",{"path":189,"title":190,"stem":191},"\u002Fshockwave-curriculum\u002Flessons\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch","Exceptions & try\u002Fcatch","shockwave-curriculum\u002Flessons\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch",{"path":193,"title":194,"stem":195},"\u002Fshockwave-curriculum\u002Flessons\u002Fch13-common-gotchas\u002F13-common-gotchas","Common Gotchas","shockwave-curriculum\u002Flessons\u002Fch13-common-gotchas\u002F13-common-gotchas",{"path":197,"title":198,"stem":199},"\u002Fshockwave-curriculum\u002Flessons\u002Fch14-why-design-patterns\u002F14-why-design-patterns","Why Design Patterns?","shockwave-curriculum\u002Flessons\u002Fch14-why-design-patterns\u002F14-why-design-patterns",{"path":201,"title":202,"stem":203},"\u002Fshockwave-curriculum\u002Flessons\u002Fch15-advanced-collections\u002F15-advanced-collections","Advanced Collections (Set\u002FQueue\u002FMap)","shockwave-curriculum\u002Flessons\u002Fch15-advanced-collections\u002F15-advanced-collections",{"path":205,"title":206,"stem":207},"\u002Fshockwave-curriculum\u002Flessons\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics","Writing Your Own Generics","shockwave-curriculum\u002Flessons\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics",{"path":209,"title":210,"stem":211},"\u002Fshockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F1-inheritance-superclass-subclass","Inheritance, Superclass, Subclass","shockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F17.1-inheritance-superclass-subclass",{"path":213,"title":214,"stem":215},"\u002Fshockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F2-inheritance-and-constructors","Inheritance and Constructors","shockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F17.2-inheritance-and-constructors",{"path":217,"title":218,"stem":219},"\u002Fshockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F3-inheritance-hierarchies","Inheritance Hierarchies","shockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F17.3-inheritance-hierarchies",{"path":221,"title":222,"stem":223},"\u002Fshockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F4-object-superclass","Object Superclass","shockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F17.4-object-superclass",{"path":225,"title":226,"stem":227},"\u002Fshockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F5-abstract-classes-and-methods","Abstract Classes and Methods","shockwave-curriculum\u002Flessons\u002Fch17-inheritance-and-abstractions\u002F17.5-abstract-classes-and-methods",{"path":229,"title":230,"stem":231},"\u002Fshockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F1-overriding-methods","Overriding Methods","shockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F18.1-overriding-methods",{"path":233,"title":234,"stem":235},"\u002Fshockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F2-super-keyword","super Keyword","shockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F18.2-super-keyword",{"path":237,"title":238,"stem":239},"\u002Fshockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F3-polymorphism","Polymorphism","shockwave-curriculum\u002Flessons\u002Fch18-polymorphism-many-forms\u002F18.3-polymorphism",{"path":241,"title":242,"stem":243},"\u002Fshockwave-curriculum\u002Flessons\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts","Interfaces as Contracts","shockwave-curriculum\u002Flessons\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts",{"path":245,"title":246,"stem":247},"\u002Fshockwave-curriculum\u002Flessons\u002Fch19-interfaces-as-contracts\u002F1-lambdas-and-method-references","Lambdas & Method References","shockwave-curriculum\u002Flessons\u002Fch19-interfaces-as-contracts\u002F19.1-lambdas-and-method-references",{"path":249,"title":250,"stem":251},"\u002Fshockwave-curriculum\u002Flessons\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern","The IO-Layer Pattern","shockwave-curriculum\u002Flessons\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern",{"path":253,"title":254,"stem":255},"\u002Fshockwave-curriculum\u002Flessons\u002Fch21-static-factories\u002F21-static-factories","Static Factories","shockwave-curriculum\u002Flessons\u002Fch21-static-factories\u002F21-static-factories",{"path":257,"title":258,"stem":259},"\u002Fshockwave-curriculum\u002Flessons\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern","The Builder Pattern","shockwave-curriculum\u002Flessons\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern",{"path":261,"title":262,"stem":263},"\u002Fshockwave-curriculum\u002Flessons\u002Fch23-encapsulation-and-final\u002F1-scope-and-access","Access, final, and Immutability","shockwave-curriculum\u002Flessons\u002Fch23-encapsulation-and-final\u002F23.1-scope-and-access",{"path":265,"title":266,"stem":267},"\u002Fshockwave-curriculum\u002Flessons\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions","Optional: Avoiding Null Pointer Exceptions","shockwave-curriculum\u002Flessons\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions",{"path":269,"title":270,"stem":271},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F1-what-is-command-based-programming","What Is Command-Based Programming?","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.1-what-is-command-based-programming",{"path":273,"title":274,"stem":275},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F2-commands-and-command-compositions","Commands & Command Compositions","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.2-commands-and-command-compositions",{"path":277,"title":278,"stem":279},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F3-the-command-scheduler","The Command Scheduler","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.3-the-command-scheduler",{"path":281,"title":282,"stem":283},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F4-state-machines-logic","State Machines: Logic","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.4-state-machines-logic",{"path":285,"title":286,"stem":287},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F5-managing-transitions","Managing Transitions","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.5-managing-transitions",{"path":289,"title":290,"stem":291},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F6-binding-commands-to-triggers","Binding Commands to Triggers","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.6-binding-commands-to-triggers",{"path":293,"title":294,"stem":295},"\u002Fshockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F7-structuring-a-command-based-robot-project","Structuring a Command-Based Robot Project","shockwave-curriculum\u002Flessons\u002Fch25-command-based-programming\u002F25.7-structuring-a-command-based-robot-project",{"path":297,"title":298,"stem":299},"\u002Fshockwave-curriculum\u002Flessons\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways","Architecture Takeaways","shockwave-curriculum\u002Flessons\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways",{"path":301,"title":302,"stem":303},"\u002Fshockwave-curriculum\u002Flessons\u002Fch27-program-design-and-abstraction\u002F1-abstraction-and-program-design","Abstraction and Program Design","shockwave-curriculum\u002Flessons\u002Fch27-program-design-and-abstraction\u002F27.1-abstraction-and-program-design",{"path":305,"title":306,"stem":307},"\u002Fshockwave-curriculum\u002Flessons\u002Fch27-program-design-and-abstraction\u002F2-impact-of-program-design","Impact of Program Design","shockwave-curriculum\u002Flessons\u002Fch27-program-design-and-abstraction\u002F27.2-impact-of-program-design",{"path":309,"title":310,"stem":311},"\u002Fshockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F1-searching-algorithms","Searching Algorithms","shockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F28.1-searching-algorithms",{"path":313,"title":314,"stem":315},"\u002Fshockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F2-sorting-algorithms","Sorting Algorithms","shockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F28.2-sorting-algorithms",{"path":317,"title":318,"stem":319},"\u002Fshockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F3-recursion","Recursion","shockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F28.3-recursion",{"path":321,"title":322,"stem":323},"\u002Fshockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F4-recursive-searching-and-sorting","Recursive Searching and Sorting","shockwave-curriculum\u002Flessons\u002Fch28-algorithms-searching-sorting-recursion\u002F28.4-recursive-searching-and-sorting",{"path":325,"title":326,"stem":327},"\u002Fshockwave-curriculum\u002Flessons\u002Fch29-git-and-github-basics\u002F1-coming-soon","Git & GitHub Basics — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch29-git-and-github-basics\u002F29.1-coming-soon",{"path":329,"title":330,"stem":331},"\u002Fshockwave-curriculum\u002Flessons\u002Fch30-git-history-and-merging\u002F1-coming-soon","Git — History & Merging — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch30-git-history-and-merging\u002F30.1-coming-soon",{"path":333,"title":334,"stem":335},"\u002Fshockwave-curriculum\u002Flessons\u002Fch31-dev-environment-and-tooling\u002F1-coming-soon","Dev Environment & Tooling — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch31-dev-environment-and-tooling\u002F31.1-coming-soon",{"path":337,"title":338,"stem":339},"\u002Fshockwave-curriculum\u002Flessons\u002Fch32-unit-testing\u002F1-coming-soon","Unit Testing — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch32-unit-testing\u002F32.1-coming-soon",{"path":341,"title":342,"stem":343},"\u002Fshockwave-curriculum\u002Flessons\u002Fch33-advantagekit-autologging\u002F1-coming-soon","AdvantageKit — AutoLogging — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch33-advantagekit-autologging\u002F33.1-coming-soon",{"path":345,"title":346,"stem":347},"\u002Fshockwave-curriculum\u002Flessons\u002Fch34-log-replay\u002F1-coming-soon","Log Replay — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch34-log-replay\u002F34.1-coming-soon",{"path":349,"title":350,"stem":351},"\u002Fshockwave-curriculum\u002Flessons\u002Fch35-advantagescope-i-visualization\u002F1-coming-soon","AdvantageScope I: Visualization — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch35-advantagescope-i-visualization\u002F35.1-coming-soon",{"path":353,"title":354,"stem":355},"\u002Fshockwave-curriculum\u002Flessons\u002Fch36-advantagescope-ii-custom-3d-assets\u002F1-coming-soon","AdvantageScope II: Custom 3D Assets — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch36-advantagescope-ii-custom-3d-assets\u002F36.1-coming-soon",{"path":357,"title":358,"stem":359},"\u002Fshockwave-curriculum\u002Flessons\u002Fch37-autonomous-i\u002F1-coming-soon","Autonomous I — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch37-autonomous-i\u002F37.1-coming-soon",{"path":361,"title":362,"stem":363},"\u002Fshockwave-curriculum\u002Flessons\u002Fch38-autonomous-ii-pathplanner-and-trajectories\u002F1-coming-soon","Autonomous II: PathPlanner & Trajectories — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch38-autonomous-ii-pathplanner-and-trajectories\u002F38.1-coming-soon",{"path":365,"title":366,"stem":367},"\u002Fshockwave-curriculum\u002Flessons\u002Fch39-control-fundamentals\u002F1-coming-soon","Control Fundamentals — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch39-control-fundamentals\u002F39.1-coming-soon",{"path":369,"title":370,"stem":371},"\u002Fshockwave-curriculum\u002Flessons\u002Fch40-motion-profiles\u002F1-coming-soon","Motion Profiles — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch40-motion-profiles\u002F40.1-coming-soon",{"path":373,"title":374,"stem":375},"\u002Fshockwave-curriculum\u002Flessons\u002Fch41-hardware-fundamentals\u002F1-coming-soon","Hardware Fundamentals — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch41-hardware-fundamentals\u002F41.1-coming-soon",{"path":377,"title":378,"stem":379},"\u002Fshockwave-curriculum\u002Flessons\u002Fch42-photonvision\u002F1-coming-soon","PhotonVision — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch42-photonvision\u002F42.1-coming-soon",{"path":381,"title":382,"stem":383},"\u002Fshockwave-curriculum\u002Flessons\u002Fch43-apriltags-and-pose\u002F1-coming-soon","AprilTags & Pose — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch43-apriltags-and-pose\u002F43.1-coming-soon",{"path":385,"title":386,"stem":387},"\u002Fshockwave-curriculum\u002Flessons\u002Fch44-subsystems-i\u002F1-coming-soon","Subsystems I — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch44-subsystems-i\u002F44.1-coming-soon",{"path":389,"title":390,"stem":391},"\u002Fshockwave-curriculum\u002Flessons\u002Fch45-subsystems-ii-advanced\u002F1-coming-soon","Subsystems II — Advanced — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch45-subsystems-ii-advanced\u002F45.1-coming-soon",{"path":393,"title":394,"stem":395},"\u002Fshockwave-curriculum\u002Flessons\u002Fch46-team-utilities-i\u002F1-coming-soon","Team Utilities I — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch46-team-utilities-i\u002F46.1-coming-soon",{"path":397,"title":398,"stem":399},"\u002Fshockwave-curriculum\u002Flessons\u002Fch47-field-constants\u002F1-coming-soon","Field Constants — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch47-field-constants\u002F47.1-coming-soon",{"path":401,"title":402,"stem":403},"\u002Fshockwave-curriculum\u002Flessons\u002Fch48-troubleshooting-i-runtime-debug\u002F1-coming-soon","Troubleshooting I — Runtime Debug — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch48-troubleshooting-i-runtime-debug\u002F48.1-coming-soon",{"path":405,"title":406,"stem":407},"\u002Fshockwave-curriculum\u002Flessons\u002Fch49-troubleshooting-ii-can-and-sim\u002F1-coming-soon","Troubleshooting II: CAN & Sim — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch49-troubleshooting-ii-can-and-sim\u002F49.1-coming-soon",{"path":409,"title":410,"stem":411},"\u002Fshockwave-curriculum\u002Flessons\u002Fch50-vendor-libraries-talonfx\u002F1-coming-soon","Vendor Libraries: TalonFX — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch50-vendor-libraries-talonfx\u002F50.1-coming-soon",{"path":413,"title":414,"stem":415},"\u002Fshockwave-curriculum\u002Flessons\u002Fch51-robot-alerts\u002F1-coming-soon","Robot Alerts — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch51-robot-alerts\u002F51.1-coming-soon",{"path":417,"title":418,"stem":419},"\u002Fshockwave-curriculum\u002Flessons\u002Fch52-wpilib-commands\u002F1-coming-soon","WPILib Commands — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch52-wpilib-commands\u002F52.1-coming-soon",{"path":421,"title":422,"stem":423},"\u002Fshockwave-curriculum\u002Flessons\u002Fch53-wpilib-geometry\u002F1-coming-soon","WPILib Geometry — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch53-wpilib-geometry\u002F53.1-coming-soon",{"path":425,"title":426,"stem":427},"\u002Fshockwave-curriculum\u002Flessons\u002Fch54-networktables\u002F1-coming-soon","NetworkTables — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch54-networktables\u002F54.1-coming-soon",{"path":429,"title":430,"stem":431},"\u002Fshockwave-curriculum\u002Flessons\u002Fch55-command-scheduler\u002F1-coming-soon","Command Scheduler — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch55-command-scheduler\u002F55.1-coming-soon",{"path":433,"title":434,"stem":435},"\u002Fshockwave-curriculum\u002Flessons\u002Fch56-wpilib-timers\u002F1-coming-soon","WPILib Timers — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch56-wpilib-timers\u002F56.1-coming-soon",{"path":437,"title":438,"stem":439},"\u002Fshockwave-curriculum\u002Flessons\u002Fch57-wpilib-triggers\u002F1-coming-soon","WPILib Triggers — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch57-wpilib-triggers\u002F57.1-coming-soon",{"path":441,"title":442,"stem":443},"\u002Fshockwave-curriculum\u002Flessons\u002Fch58-vendor-units-and-conversions\u002F1-coming-soon","Vendor Units & Conversions — Coming Soon","shockwave-curriculum\u002Flessons\u002Fch58-vendor-units-and-conversions\u002F58.1-coming-soon",[445,449,453,457,461,465,469,473,477,481,485,489,493,497,501,505,509,513,517,521,525,529,533,537,541,545,549,553,557,561,565,569,573,577,581,585,589,593,597,601,605,609,613,617,621,625,629,633,637,641,645,649,653,657,661,665,669,673,677,681,685,689,693,697,701,705,709,713,717,721,725,729,733,737,741,745,749],{"path":446,"title":447,"stem":448},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch01-why-java-for-frc\u002F2-intro-to-algorithms-programming-and-compilers","Intro to Algorithms, Programming and Compilers — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch01-why-java-for-frc\u002F1.2-intro-to-algorithms-programming-and-compilers",{"path":450,"title":451,"stem":452},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F1-variables-and-data-types","Variables & Data Types — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2.1-variables-and-data-types",{"path":454,"title":455,"stem":456},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2-expressions-and-output","Expressions & Output — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2.2-expressions-and-output",{"path":458,"title":459,"stem":460},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F3-assignment-and-input","Assignment & Input — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2.3-assignment-and-input",{"path":462,"title":463,"stem":464},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F4-casting-and-ranges-of-values","Casting & Ranges of Values — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2.4-casting-and-ranges-of-values",{"path":466,"title":467,"stem":468},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F5-compound-assignment-operators","Compound Assignment Operators — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch02-variables-and-types\u002F2.5-compound-assignment-operators",{"path":470,"title":471,"stem":472},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F1-apis-and-libraries","APIs and Libraries — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F3.1-apis-and-libraries",{"path":474,"title":475,"stem":476},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F2-documentation-with-comments-and-preconditions","Documentation with Comments and Preconditions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F3.2-documentation-with-comments-and-preconditions",{"path":478,"title":479,"stem":480},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F3-packages-and-imports","Packages & Imports — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch03-apis-libraries-and-documentation\u002F3.3-packages-and-imports",{"path":482,"title":483,"stem":484},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F1-methods-signatures-and-parameters","Methods, Signatures & Parameters — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.1-methods-signatures-and-parameters",{"path":486,"title":487,"stem":488},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F2-calling-class-methods","Calling Class Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.2-calling-class-methods",{"path":490,"title":491,"stem":492},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F3-using-the-math-class","Using the Math Class — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.3-using-the-math-class",{"path":494,"title":495,"stem":496},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4-objects-instances-of-classes","Objects — Instances of Classes — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.4-objects-instances-of-classes",{"path":498,"title":499,"stem":500},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F5-creating-and-initializing-objects-constructors","Creating & Initializing Objects: Constructors — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.5-creating-and-initializing-objects-constructors",{"path":502,"title":503,"stem":504},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F6-calling-instance-methods","Calling Instance Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch04-using-objects-and-calling-methods\u002F4.6-calling-instance-methods",{"path":506,"title":507,"stem":508},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F1-5.2-if-statements-and-for-loops","if Statements & For Loops — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.1-5.2-if-statements-and-for-loops",{"path":510,"title":511,"stem":512},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F10-nested-iteration","Nested Iteration — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.10-nested-iteration",{"path":514,"title":515,"stem":516},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F11-informal-runtime-analysis-of-loops","Informal Runtime Analysis of Loops — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.11-informal-runtime-analysis-of-loops",{"path":518,"title":519,"stem":520},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F12-switch-statements-and-expressions","switch Statements and Expressions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.12-switch-statements-and-expressions",{"path":522,"title":523,"stem":524},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F3-algorithms-with-selection-and-repetition","Algorithms with Selection and Repetition — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.3-algorithms-with-selection-and-repetition",{"path":526,"title":527,"stem":528},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F4-boolean-expressions","Boolean Expressions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.4-boolean-expressions",{"path":530,"title":531,"stem":532},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5-nested-if-statements","Nested if Statements — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.5-nested-if-statements",{"path":534,"title":535,"stem":536},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F6-compound-boolean-expressions","Compound Boolean Expressions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.6-compound-boolean-expressions",{"path":538,"title":539,"stem":540},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F7-comparing-boolean-expressions-de-morgans-laws","Comparing Boolean Expressions (De Morgan's Laws) — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.7-comparing-boolean-expressions-de-morgans-laws",{"path":542,"title":543,"stem":544},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F8-while-loops","While Loops — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.8-while-loops",{"path":546,"title":547,"stem":548},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F9-implementing-selection-and-iteration-algorithms","Implementing Selection and Iteration Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch05-control-structures\u002F5.9-implementing-selection-and-iteration-algorithms",{"path":550,"title":551,"stem":552},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch06-strings\u002F1-strings","Strings — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch06-strings\u002F6.1-strings",{"path":554,"title":555,"stem":556},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch06-strings\u002F2-string-algorithms","String Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch06-strings\u002F6.2-string-algorithms",{"path":558,"title":559,"stem":560},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F1-anatomy-of-a-java-class","Anatomy of a Java Class — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F7.1-anatomy-of-a-java-class",{"path":562,"title":563,"stem":564},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F2-methods-how-to-write-them","Methods: How to Write Them — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F7.2-methods-how-to-write-them",{"path":566,"title":567,"stem":568},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F3-methods-passing-and-returning-references-of-an-object","Methods: Passing & Returning References of an Object — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F7.3-methods-passing-and-returning-references-of-an-object",{"path":570,"title":571,"stem":572},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F4-class-static-variables-and-methods","Class (static) Variables & Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch07-the-class-blueprint\u002F7.4-class-static-variables-and-methods",{"path":574,"title":575,"stem":576},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch08-constructors-and-this\u002F1-8.2-constructors-and-this","Constructors & \"this\" — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch08-constructors-and-this\u002F8.1-8.2-constructors-and-this",{"path":578,"title":579,"stem":580},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F1-array-creation-and-access","Array Creation and Access — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.1-array-creation-and-access",{"path":582,"title":583,"stem":584},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F2-arraylist-and-its-methods","ArrayList and its Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.2-arraylist-and-its-methods",{"path":586,"title":587,"stem":588},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F3-optional-hashmap-dictionary-data-structure","HashMap (Dictionary) Data Structure — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.3-optional-hashmap-dictionary-data-structure",{"path":590,"title":591,"stem":592},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F4-array-traversals","Array Traversals — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.4-array-traversals",{"path":594,"title":595,"stem":596},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F5-implementing-array-algorithms","Implementing Array Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.5-implementing-array-algorithms",{"path":598,"title":599,"stem":600},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F6-arraylist-traversals","ArrayList Traversals — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.6-arraylist-traversals",{"path":602,"title":603,"stem":604},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F7-implementing-arraylist-algorithms","Implementing ArrayList Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.7-implementing-arraylist-algorithms",{"path":606,"title":607,"stem":608},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F8-using-text-files","Using Text Files — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch09-storing-data\u002F9.8-using-text-files",{"path":610,"title":611,"stem":612},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F1-2d-array-creation-and-access","2D Array Creation and Access — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F10.1-2d-array-creation-and-access",{"path":614,"title":615,"stem":616},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F2-2d-array-traversals-nested-loops","2D Array Traversals: Nested Loops — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F10.2-2d-array-traversals-nested-loops",{"path":618,"title":619,"stem":620},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F3-implementing-2d-array-algorithms","Implementing 2D Array Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch10-2d-arrays\u002F10.3-implementing-2d-array-algorithms",{"path":622,"title":623,"stem":624},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch11-enums-named-choices\u002F11-enums-named-choices","Enums: Named Choices — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch11-enums-named-choices\u002F11-enums-named-choices",{"path":626,"title":627,"stem":628},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch","Exceptions & try\u002Fcatch — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch",{"path":630,"title":631,"stem":632},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch13-common-gotchas\u002F13-common-gotchas","Common Gotchas — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch13-common-gotchas\u002F13-common-gotchas",{"path":634,"title":635,"stem":636},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch15-advanced-collections\u002F15-advanced-collections","Advanced Collections (Set\u002FQueue\u002FMap) — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch15-advanced-collections\u002F15-advanced-collections",{"path":638,"title":639,"stem":640},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics","Writing Your Own Generics — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics",{"path":642,"title":643,"stem":644},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F1-inheritance-superclass-subclass","Inheritance, Superclass, Subclass — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F17.1-inheritance-superclass-subclass",{"path":646,"title":647,"stem":648},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F2-inheritance-and-constructors","Inheritance and Constructors — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F17.2-inheritance-and-constructors",{"path":650,"title":651,"stem":652},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F3-inheritance-hierarchies","Inheritance Hierarchies — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F17.3-inheritance-hierarchies",{"path":654,"title":655,"stem":656},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F4-object-superclass","Object Superclass — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F17.4-object-superclass",{"path":658,"title":659,"stem":660},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F5-abstract-classes-and-methods","Abstract Classes and Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch17-inheritance-and-abstractions\u002F17.5-abstract-classes-and-methods",{"path":662,"title":663,"stem":664},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F1-overriding-methods","Overriding Methods — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F18.1-overriding-methods",{"path":666,"title":667,"stem":668},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F2-super-keyword","super Keyword — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F18.2-super-keyword",{"path":670,"title":671,"stem":672},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F3-polymorphism","Polymorphism — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch18-polymorphism-many-forms\u002F18.3-polymorphism",{"path":674,"title":675,"stem":676},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts","Interfaces as Contracts — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts",{"path":678,"title":679,"stem":680},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch19-interfaces-as-contracts\u002F1-lambdas-and-method-references","Lambdas & Method References — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch19-interfaces-as-contracts\u002F19.1-lambdas-and-method-references",{"path":682,"title":683,"stem":684},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern","The IO-Layer Pattern — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern",{"path":686,"title":687,"stem":688},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch21-static-factories\u002F21-static-factories","Static Factories — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch21-static-factories\u002F21-static-factories",{"path":690,"title":691,"stem":692},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern","The Builder Pattern — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern",{"path":694,"title":695,"stem":696},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch23-encapsulation-and-final\u002F1-scope-and-access","Access, final, and Immutability — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch23-encapsulation-and-final\u002F23.1-scope-and-access",{"path":698,"title":699,"stem":700},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions","Optional: Avoiding Null Pointer Exceptions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions",{"path":702,"title":703,"stem":704},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F1-what-is-command-based-programming","What Is Command-Based Programming? — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.1-what-is-command-based-programming",{"path":706,"title":707,"stem":708},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F2-commands-and-command-compositions","Commands & Command Compositions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.2-commands-and-command-compositions",{"path":710,"title":711,"stem":712},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F3-the-command-scheduler","The Command Scheduler — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.3-the-command-scheduler",{"path":714,"title":715,"stem":716},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F4-state-machines-logic","State Machines: Logic — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.4-state-machines-logic",{"path":718,"title":719,"stem":720},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F5-managing-transitions","Managing Transitions — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.5-managing-transitions",{"path":722,"title":723,"stem":724},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F6-binding-commands-to-triggers","Binding Commands to Triggers — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.6-binding-commands-to-triggers",{"path":726,"title":727,"stem":728},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F7-structuring-a-command-based-robot-project","Structuring a Command-Based Robot Project — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch25-command-based-programming\u002F25.7-structuring-a-command-based-robot-project",{"path":730,"title":731,"stem":732},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways","Architecture Takeaways — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways",{"path":734,"title":735,"stem":736},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch27-program-design-and-abstraction\u002F1-abstraction-and-program-design","Abstraction and Program Design — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch27-program-design-and-abstraction\u002F27.1-abstraction-and-program-design",{"path":738,"title":739,"stem":740},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F1-searching-algorithms","Searching Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F28.1-searching-algorithms",{"path":742,"title":743,"stem":744},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F2-sorting-algorithms","Sorting Algorithms — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F28.2-sorting-algorithms",{"path":746,"title":747,"stem":748},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F3-recursion","Recursion — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F28.3-recursion",{"path":750,"title":751,"stem":752},"\u002Fshockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F4-recursive-searching-and-sorting","Recursive Searching and Sorting — Worked Example","shockwave-curriculum\u002Fexamples\u002Fch28-algorithms-searching-sorting-recursion\u002F28.4-recursive-searching-and-sorting",[754,758,762,766,770,774,778,782,786,790,794,798,802,806,810,814,818,822,826,830,834,838,842,846,850,854,858,862,866,870,874,878,882,886,890,894,898,902,906,910,914,918,922,926,930,934,938,942,946,950,954,958,962,966,970,974,978,982,986,990,994,998,1002,1006,1010,1014,1018,1022,1026,1030,1034,1038,1042,1046,1050,1054,1058,1062,1066],{"path":755,"title":756,"stem":757},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch01-why-java-for-frc\u002F2-intro-to-algorithms-programming-and-compilers","Intro to Algorithms, Programming and Compilers — Exercises","shockwave-curriculum\u002Fexercises\u002Fch01-why-java-for-frc\u002F1.2-intro-to-algorithms-programming-and-compilers",{"path":759,"title":760,"stem":761},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F1-variables-and-data-types","Variables & Data Types — Exercises","shockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2.1-variables-and-data-types",{"path":763,"title":764,"stem":765},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2-expressions-and-output","Expressions & Output — Exercises","shockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2.2-expressions-and-output",{"path":767,"title":768,"stem":769},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F3-assignment-and-input","Assignment & Input — Exercises","shockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2.3-assignment-and-input",{"path":771,"title":772,"stem":773},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F4-casting-and-ranges-of-values","Casting & Ranges of Values — Exercises","shockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2.4-casting-and-ranges-of-values",{"path":775,"title":776,"stem":777},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F5-compound-assignment-operators","Compound Assignment Operators — Exercises","shockwave-curriculum\u002Fexercises\u002Fch02-variables-and-types\u002F2.5-compound-assignment-operators",{"path":779,"title":780,"stem":781},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F1-apis-and-libraries","APIs and Libraries — Exercises","shockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F3.1-apis-and-libraries",{"path":783,"title":784,"stem":785},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F2-documentation-with-comments-and-preconditions","Documentation with Comments and Preconditions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F3.2-documentation-with-comments-and-preconditions",{"path":787,"title":788,"stem":789},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F3-packages-and-imports","Packages & Imports — Exercises","shockwave-curriculum\u002Fexercises\u002Fch03-apis-libraries-and-documentation\u002F3.3-packages-and-imports",{"path":791,"title":792,"stem":793},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F1-methods-signatures-and-parameters","Methods, Signatures & Parameters — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.1-methods-signatures-and-parameters",{"path":795,"title":796,"stem":797},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F2-calling-class-methods","Calling Class Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.2-calling-class-methods",{"path":799,"title":800,"stem":801},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F3-using-the-math-class","Using the Math Class — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.3-using-the-math-class",{"path":803,"title":804,"stem":805},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4-objects-instances-of-classes","Objects — Instances of Classes — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.4-objects-instances-of-classes",{"path":807,"title":808,"stem":809},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F5-creating-and-initializing-objects-constructors","Creating & Initializing Objects: Constructors — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.5-creating-and-initializing-objects-constructors",{"path":811,"title":812,"stem":813},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F6-calling-instance-methods","Calling Instance Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch04-using-objects-and-calling-methods\u002F4.6-calling-instance-methods",{"path":815,"title":816,"stem":817},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F1-5.2-if-statements-and-for-loops","if Statements & For Loops — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.1-5.2-if-statements-and-for-loops",{"path":819,"title":820,"stem":821},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F10-nested-iteration","Nested Iteration — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.10-nested-iteration",{"path":823,"title":824,"stem":825},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F11-informal-runtime-analysis-of-loops","Informal Runtime Analysis of Loops — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.11-informal-runtime-analysis-of-loops",{"path":827,"title":828,"stem":829},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F12-switch-statements-and-expressions","switch Statements and Expressions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.12-switch-statements-and-expressions",{"path":831,"title":832,"stem":833},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F3-algorithms-with-selection-and-repetition","Algorithms with Selection and Repetition — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.3-algorithms-with-selection-and-repetition",{"path":835,"title":836,"stem":837},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F4-boolean-expressions","Boolean Expressions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.4-boolean-expressions",{"path":839,"title":840,"stem":841},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5-nested-if-statements","Nested if Statements — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.5-nested-if-statements",{"path":843,"title":844,"stem":845},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F6-compound-boolean-expressions","Compound Boolean Expressions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.6-compound-boolean-expressions",{"path":847,"title":848,"stem":849},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F7-comparing-boolean-expressions-de-morgans-laws","Comparing Boolean Expressions (De Morgan's Laws) — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.7-comparing-boolean-expressions-de-morgans-laws",{"path":851,"title":852,"stem":853},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F8-while-loops","While Loops — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.8-while-loops",{"path":855,"title":856,"stem":857},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F9-implementing-selection-and-iteration-algorithms","Implementing Selection and Iteration Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch05-control-structures\u002F5.9-implementing-selection-and-iteration-algorithms",{"path":859,"title":860,"stem":861},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch06-strings\u002F1-strings","Strings — Exercises","shockwave-curriculum\u002Fexercises\u002Fch06-strings\u002F6.1-strings",{"path":863,"title":864,"stem":865},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch06-strings\u002F2-string-algorithms","String Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch06-strings\u002F6.2-string-algorithms",{"path":867,"title":868,"stem":869},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F1-anatomy-of-a-java-class","Anatomy of a Java Class — Exercises","shockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F7.1-anatomy-of-a-java-class",{"path":871,"title":872,"stem":873},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F2-methods-how-to-write-them","Methods: How to Write Them — Exercises","shockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F7.2-methods-how-to-write-them",{"path":875,"title":876,"stem":877},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F3-methods-passing-and-returning-references-of-an-object","Methods: Passing & Returning References of an Object — Exercises","shockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F7.3-methods-passing-and-returning-references-of-an-object",{"path":879,"title":880,"stem":881},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F4-class-static-variables-and-methods","Class (static) Variables & Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch07-the-class-blueprint\u002F7.4-class-static-variables-and-methods",{"path":883,"title":884,"stem":885},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch08-constructors-and-this\u002F1-8.2-constructors-and-this","Constructors & \"this\" — Exercises","shockwave-curriculum\u002Fexercises\u002Fch08-constructors-and-this\u002F8.1-8.2-constructors-and-this",{"path":887,"title":888,"stem":889},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F1-array-creation-and-access","Array Creation and Access — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.1-array-creation-and-access",{"path":891,"title":892,"stem":893},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F2-arraylist-and-its-methods","ArrayList and its Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.2-arraylist-and-its-methods",{"path":895,"title":896,"stem":897},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F3-optional-hashmap-dictionary-data-structure","HashMap (Dictionary) Data Structure — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.3-optional-hashmap-dictionary-data-structure",{"path":899,"title":900,"stem":901},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F4-array-traversals","Array Traversals — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.4-array-traversals",{"path":903,"title":904,"stem":905},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F5-implementing-array-algorithms","Implementing Array Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.5-implementing-array-algorithms",{"path":907,"title":908,"stem":909},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F6-arraylist-traversals","ArrayList Traversals — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.6-arraylist-traversals",{"path":911,"title":912,"stem":913},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F7-implementing-arraylist-algorithms","Implementing ArrayList Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.7-implementing-arraylist-algorithms",{"path":915,"title":916,"stem":917},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F8-using-text-files","Using Text Files — Exercises","shockwave-curriculum\u002Fexercises\u002Fch09-storing-data\u002F9.8-using-text-files",{"path":919,"title":920,"stem":921},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F1-2d-array-creation-and-access","2D Array Creation and Access — Exercises","shockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F10.1-2d-array-creation-and-access",{"path":923,"title":924,"stem":925},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F2-2d-array-traversals-nested-loops","2D Array Traversals: Nested Loops — Exercises","shockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F10.2-2d-array-traversals-nested-loops",{"path":927,"title":928,"stem":929},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F3-implementing-2d-array-algorithms","Implementing 2D Array Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch10-2d-arrays\u002F10.3-implementing-2d-array-algorithms",{"path":931,"title":932,"stem":933},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch11-enums-named-choices\u002F11-enums-named-choices","Enums: Named Choices — Exercises","shockwave-curriculum\u002Fexercises\u002Fch11-enums-named-choices\u002F11-enums-named-choices",{"path":935,"title":936,"stem":937},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch","Exceptions & try\u002Fcatch — Exercises","shockwave-curriculum\u002Fexercises\u002Fch12-exceptions-and-try-catch\u002F12-exceptions-and-try-catch",{"path":939,"title":940,"stem":941},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch13-common-gotchas\u002F13-common-gotchas","Common Gotchas — Exercises","shockwave-curriculum\u002Fexercises\u002Fch13-common-gotchas\u002F13-common-gotchas",{"path":943,"title":944,"stem":945},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch14-why-design-patterns\u002F14-why-design-patterns","Why Design Patterns? — Exercises","shockwave-curriculum\u002Fexercises\u002Fch14-why-design-patterns\u002F14-why-design-patterns",{"path":947,"title":948,"stem":949},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch15-advanced-collections\u002F15-advanced-collections","Advanced Collections (Set\u002FQueue\u002FMap) — Exercises","shockwave-curriculum\u002Fexercises\u002Fch15-advanced-collections\u002F15-advanced-collections",{"path":951,"title":952,"stem":953},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics","Writing Your Own Generics — Exercises","shockwave-curriculum\u002Fexercises\u002Fch16-writing-your-own-generics\u002F16-writing-your-own-generics",{"path":955,"title":956,"stem":957},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F1-inheritance-superclass-subclass","Inheritance, Superclass, Subclass — Exercises","shockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F17.1-inheritance-superclass-subclass",{"path":959,"title":960,"stem":961},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F2-inheritance-and-constructors","Inheritance and Constructors — Exercises","shockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F17.2-inheritance-and-constructors",{"path":963,"title":964,"stem":965},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F3-inheritance-hierarchies","Inheritance Hierarchies — Exercises","shockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F17.3-inheritance-hierarchies",{"path":967,"title":968,"stem":969},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F4-object-superclass","Object Superclass — Exercises","shockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F17.4-object-superclass",{"path":971,"title":972,"stem":973},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F5-abstract-classes-and-methods","Abstract Classes and Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch17-inheritance-and-abstractions\u002F17.5-abstract-classes-and-methods",{"path":975,"title":976,"stem":977},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F1-overriding-methods","Overriding Methods — Exercises","shockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F18.1-overriding-methods",{"path":979,"title":980,"stem":981},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F2-super-keyword","super Keyword — Exercises","shockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F18.2-super-keyword",{"path":983,"title":984,"stem":985},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F3-polymorphism","Polymorphism — Exercises","shockwave-curriculum\u002Fexercises\u002Fch18-polymorphism-many-forms\u002F18.3-polymorphism",{"path":987,"title":988,"stem":989},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts","Interfaces as Contracts — Exercises","shockwave-curriculum\u002Fexercises\u002Fch19-interfaces-as-contracts\u002F19-interfaces-as-contracts",{"path":991,"title":992,"stem":993},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch19-interfaces-as-contracts\u002F1-lambdas-and-method-references","Lambdas & Method References — Exercises","shockwave-curriculum\u002Fexercises\u002Fch19-interfaces-as-contracts\u002F19.1-lambdas-and-method-references",{"path":995,"title":996,"stem":997},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern","The IO-Layer Pattern — Exercises","shockwave-curriculum\u002Fexercises\u002Fch20-the-io-layer-pattern\u002F20-the-io-layer-pattern",{"path":999,"title":1000,"stem":1001},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch21-static-factories\u002F21-static-factories","Static Factories — Exercises","shockwave-curriculum\u002Fexercises\u002Fch21-static-factories\u002F21-static-factories",{"path":1003,"title":1004,"stem":1005},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern","The Builder Pattern — Exercises","shockwave-curriculum\u002Fexercises\u002Fch22-the-builder-pattern\u002F22-the-builder-pattern",{"path":1007,"title":1008,"stem":1009},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch23-encapsulation-and-final\u002F1-scope-and-access","Access, final, and Immutability — Exercises","shockwave-curriculum\u002Fexercises\u002Fch23-encapsulation-and-final\u002F23.1-scope-and-access",{"path":1011,"title":1012,"stem":1013},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions","Optional: Avoiding Null Pointer Exceptions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions",{"path":1015,"title":1016,"stem":1017},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F1-what-is-command-based-programming","What Is Command-Based Programming? — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.1-what-is-command-based-programming",{"path":1019,"title":1020,"stem":1021},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F2-commands-and-command-compositions","Commands & Command Compositions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.2-commands-and-command-compositions",{"path":1023,"title":1024,"stem":1025},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F3-the-command-scheduler","The Command Scheduler — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.3-the-command-scheduler",{"path":1027,"title":1028,"stem":1029},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F4-state-machines-logic","State Machines: Logic — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.4-state-machines-logic",{"path":1031,"title":1032,"stem":1033},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F5-managing-transitions","Managing Transitions — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.5-managing-transitions",{"path":1035,"title":1036,"stem":1037},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F6-binding-commands-to-triggers","Binding Commands to Triggers — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.6-binding-commands-to-triggers",{"path":1039,"title":1040,"stem":1041},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F7-structuring-a-command-based-robot-project","Structuring a Command-Based Robot Project — Exercises","shockwave-curriculum\u002Fexercises\u002Fch25-command-based-programming\u002F25.7-structuring-a-command-based-robot-project",{"path":1043,"title":1044,"stem":1045},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways","Architecture Takeaways — Exercises","shockwave-curriculum\u002Fexercises\u002Fch26-architecture-takeaways\u002F26-architecture-takeaways",{"path":1047,"title":1048,"stem":1049},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch27-program-design-and-abstraction\u002F1-abstraction-and-program-design","Abstraction and Program Design — Exercises","shockwave-curriculum\u002Fexercises\u002Fch27-program-design-and-abstraction\u002F27.1-abstraction-and-program-design",{"path":1051,"title":1052,"stem":1053},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch27-program-design-and-abstraction\u002F2-impact-of-program-design","Impact of Program Design — Exercises","shockwave-curriculum\u002Fexercises\u002Fch27-program-design-and-abstraction\u002F27.2-impact-of-program-design",{"path":1055,"title":1056,"stem":1057},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F1-searching-algorithms","Searching Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F28.1-searching-algorithms",{"path":1059,"title":1060,"stem":1061},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F2-sorting-algorithms","Sorting Algorithms — Exercises","shockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F28.2-sorting-algorithms",{"path":1063,"title":1064,"stem":1065},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F3-recursion","Recursion — Exercises","shockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F28.3-recursion",{"path":1067,"title":1068,"stem":1069},"\u002Fshockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F4-recursive-searching-and-sorting","Recursive Searching and Sorting — Exercises","shockwave-curriculum\u002Fexercises\u002Fch28-algorithms-searching-sorting-recursion\u002F28.4-recursive-searching-and-sorting",{"id":1071,"title":266,"body":1072,"description":1142,"extension":1705,"meta":1706,"navigation":1220,"path":265,"seo":1709,"stem":267,"__hash__":1710},"lessons\u002Fshockwave-curriculum\u002Flessons\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions.md",{"type":1073,"value":1074,"toc":1695},"minimark",[1075,1079,1084,1107,1118,1122,1136,1195,1202,1206,1246,1258,1262,1322,1354,1381,1385,1413,1428,1449,1453,1471,1496,1510,1519,1545,1551,1555,1602,1606,1676,1691],[1076,1077,266],"h1",{"id":1078},"optional-avoiding-null-pointer-exceptions",[1080,1081,1083],"h2",{"id":1082},"the-null-problem","The Null Problem",[1085,1086,1087,1088,1092,1093,1095,1096,1099,1100,1102,1103,1106],"p",{},"Returning ",[1089,1090,1091],"code",{},"null"," to mean \"there's no value here\" is one of the most common sources of bugs in any Java program — Tony Hoare, who introduced the null reference in 1965, later called it his \"billion-dollar mistake.\" The trouble is that ",[1089,1094,1091],{}," is invisible in a method's signature: nothing about ",[1089,1097,1098],{},"Pose2d getVisionPose()"," warns a caller that it might come back ",[1089,1101,1091],{},", so it's easy to forget the check and get a ",[1089,1104,1105],{},"NullPointerException"," (Ch.12\u002F13) instead.",[1085,1108,1109,1110,1114,1115,1117],{},"The classic FRC case: a vision pose estimator can only report a robot position if a camera actually sees an AprilTag ",[1111,1112,1113],"em",{},"this frame"," — plenty of frames, it can't. Returning ",[1089,1116,1091],{}," on those frames leaves every caller responsible for remembering to check first.",[1080,1119,1121],{"id":1120},"optional-making-might-be-absent-part-of-the-type","Optional: Making \"Might Be Absent\" Part of the Type",[1085,1123,1124,1127,1128,1132,1133,1135],{},[1089,1125,1126],{},"java.util.Optional\u003CT>"," is a container that either holds a value, or is explicitly ",[1129,1130,1131],"strong",{},"empty"," — and unlike ",[1089,1134,1091],{},", that possibility is written directly into the method's return type:",[1137,1138,1143],"pre",{"className":1139,"code":1140,"language":1141,"meta":1142,"style":1142},"language-java shiki shiki-themes github-light github-dark","public Optional\u003CPose2d> getPose()\n{\n    if (!hasTargetThisFrame())\n    {\n        return Optional.empty();       \u002F\u002F explicitly \"no value\" — not null\n    }\n    return Optional.of(currentPose);   \u002F\u002F wraps a real, non-null value\n}\n","java","",[1089,1144,1145,1153,1159,1165,1171,1177,1183,1189],{"__ignoreMap":1142},[1146,1147,1150],"span",{"class":1148,"line":1149},"line",1,[1146,1151,1152],{},"public Optional\u003CPose2d> getPose()\n",[1146,1154,1156],{"class":1148,"line":1155},2,[1146,1157,1158],{},"{\n",[1146,1160,1162],{"class":1148,"line":1161},3,[1146,1163,1164],{},"    if (!hasTargetThisFrame())\n",[1146,1166,1168],{"class":1148,"line":1167},4,[1146,1169,1170],{},"    {\n",[1146,1172,1174],{"class":1148,"line":1173},5,[1146,1175,1176],{},"        return Optional.empty();       \u002F\u002F explicitly \"no value\" — not null\n",[1146,1178,1180],{"class":1148,"line":1179},6,[1146,1181,1182],{},"    }\n",[1146,1184,1186],{"class":1148,"line":1185},7,[1146,1187,1188],{},"    return Optional.of(currentPose);   \u002F\u002F wraps a real, non-null value\n",[1146,1190,1192],{"class":1148,"line":1191},8,[1146,1193,1194],{},"}\n",[1085,1196,1197,1198,1201],{},"Just by reading ",[1089,1199,1200],{},"Optional\u003CPose2d> getPose()","'s signature, a caller already knows the pose might not be there this frame — the type itself documents it, instead of relying on a comment or tribal knowledge.",[1080,1203,1205],{"id":1204},"creating-an-optional","Creating an Optional",[1137,1207,1209],{"className":1139,"code":1208,"language":1141,"meta":1142,"style":1142},"Optional\u003CPose2d> empty = Optional.empty();       \u002F\u002F definitely no value\n\n\u002F\u002F wraps a value — throws immediately if currentPose is null\nOptional\u003CPose2d> present = Optional.of(currentPose);\n\n\u002F\u002F empty if currentPose is null, present otherwise\nOptional\u003CPose2d> maybe = Optional.ofNullable(currentPose);\n",[1089,1210,1211,1216,1222,1227,1232,1236,1241],{"__ignoreMap":1142},[1146,1212,1213],{"class":1148,"line":1149},[1146,1214,1215],{},"Optional\u003CPose2d> empty = Optional.empty();       \u002F\u002F definitely no value\n",[1146,1217,1218],{"class":1148,"line":1155},[1146,1219,1221],{"emptyLinePlaceholder":1220},true,"\n",[1146,1223,1224],{"class":1148,"line":1161},[1146,1225,1226],{},"\u002F\u002F wraps a value — throws immediately if currentPose is null\n",[1146,1228,1229],{"class":1148,"line":1167},[1146,1230,1231],{},"Optional\u003CPose2d> present = Optional.of(currentPose);\n",[1146,1233,1234],{"class":1148,"line":1173},[1146,1235,1221],{"emptyLinePlaceholder":1220},[1146,1237,1238],{"class":1148,"line":1179},[1146,1239,1240],{},"\u002F\u002F empty if currentPose is null, present otherwise\n",[1146,1242,1243],{"class":1148,"line":1185},[1146,1244,1245],{},"Optional\u003CPose2d> maybe = Optional.ofNullable(currentPose);\n",[1085,1247,1248,1251,1252,1254,1255,1257],{},[1089,1249,1250],{},"Optional.of(...)"," is a deliberate safety check: if you accidentally pass it a ",[1089,1253,1091],{},", it throws right away — better to fail loudly at the source than to silently wrap a ",[1089,1256,1091],{}," and have it surface as a confusing failure somewhere else later.",[1080,1259,1261],{"id":1260},"handling-both-cases-honestly","Handling Both Cases Honestly",[1137,1263,1265],{"className":1139,"code":1264,"language":1141,"meta":1142,"style":1142},"Optional\u003CPose2d> visionPose = vision.getPose();\n\n\u002F\u002F Run logic only when a value exists\nvisionPose.ifPresent(pose -> estimator.addVisionMeasurement(pose, timestamp));\n\n\u002F\u002F Or supply a fallback value for the empty case\nPose2d fallbackPose = visionPose.orElse(lastKnownPose);\n\n\u002F\u002F Or throw a specific exception if a value was truly required\nPose2d requiredPose = visionPose.orElseThrow(\n    () -> new IllegalStateException(\"No vision pose\"));\n",[1089,1266,1267,1272,1276,1281,1286,1290,1295,1300,1304,1310,1316],{"__ignoreMap":1142},[1146,1268,1269],{"class":1148,"line":1149},[1146,1270,1271],{},"Optional\u003CPose2d> visionPose = vision.getPose();\n",[1146,1273,1274],{"class":1148,"line":1155},[1146,1275,1221],{"emptyLinePlaceholder":1220},[1146,1277,1278],{"class":1148,"line":1161},[1146,1279,1280],{},"\u002F\u002F Run logic only when a value exists\n",[1146,1282,1283],{"class":1148,"line":1167},[1146,1284,1285],{},"visionPose.ifPresent(pose -> estimator.addVisionMeasurement(pose, timestamp));\n",[1146,1287,1288],{"class":1148,"line":1173},[1146,1289,1221],{"emptyLinePlaceholder":1220},[1146,1291,1292],{"class":1148,"line":1179},[1146,1293,1294],{},"\u002F\u002F Or supply a fallback value for the empty case\n",[1146,1296,1297],{"class":1148,"line":1185},[1146,1298,1299],{},"Pose2d fallbackPose = visionPose.orElse(lastKnownPose);\n",[1146,1301,1302],{"class":1148,"line":1191},[1146,1303,1221],{"emptyLinePlaceholder":1220},[1146,1305,1307],{"class":1148,"line":1306},9,[1146,1308,1309],{},"\u002F\u002F Or throw a specific exception if a value was truly required\n",[1146,1311,1313],{"class":1148,"line":1312},10,[1146,1314,1315],{},"Pose2d requiredPose = visionPose.orElseThrow(\n",[1146,1317,1319],{"class":1148,"line":1318},11,[1146,1320,1321],{},"    () -> new IllegalStateException(\"No vision pose\"));\n",[1085,1323,1324,1327,1328,1331,1332,1335,1336,1339,1340,1343,1344,1346,1347,1349,1350,1353],{},[1089,1325,1326],{},"ifPresent"," runs a lambda (Lesson 19.1) only if a value is actually there — nothing happens otherwise. ",[1089,1329,1330],{},"orElse"," supplies a fallback value for the empty case. ",[1089,1333,1334],{},"orElseThrow"," is for the rarer case where an empty ",[1089,1337,1338],{},"Optional"," really does mean something has gone wrong, and continuing anyway wouldn't make sense — passing it a lambda that builds the exception (rather than a bare ",[1089,1341,1342],{},"new IllegalStateException(...)",") matters here: ",[1089,1345,1334],{}," only constructs and throws that exception when the ",[1089,1348,1338],{}," really is empty, instead of building it eagerly every time. (You'll also see ",[1089,1351,1352],{},"orElseThrow(IllegalStateException::new)"," written as a constructor reference in other code — Lesson 19.1 has the full table of method-reference kinds, including that one.)",[1085,1355,1356,1358,1359,1362,1363,1366,1367,1370,1371,1373,1374,1377,1378,1380],{},[1089,1357,1338],{}," also has a few less common but genuinely useful methods: a no-argument ",[1089,1360,1361],{},"orElseThrow()"," (throws ",[1089,1364,1365],{},"NoSuchElementException"," when nothing more specific is needed), ",[1089,1368,1369],{},"orElseGet(supplier)"," (like ",[1089,1372,1330],{},", but only computes its fallback value when it's actually needed, instead of always), and ",[1089,1375,1376],{},"ifPresentOrElse(consumer, runnable)"," (runs one callback if a value is present, and a different one if it's empty — ",[1089,1379,1326],{}," alone has no \"else\").",[1080,1382,1384],{"id":1383},"the-one-pitfall-that-defeats-the-whole-point","The One Pitfall That Defeats the Whole Point",[1085,1386,1387,1389,1390,1393,1394,1397,1398,1400,1401,1403,1404,1406,1407,1409,1410,1412],{},[1089,1388,1338],{}," has an ",[1089,1391,1392],{},"isPresent()"," check and a ",[1089,1395,1396],{},"get()"," method that returns the wrapped value — but calling ",[1089,1399,1396],{}," without checking ",[1089,1402,1392],{}," first throws ",[1089,1405,1365],{}," on an empty ",[1089,1408,1338],{},", which is exactly the same class of crash ",[1089,1411,1338],{}," exists to prevent, just under a different exception name:",[1137,1414,1416],{"className":1139,"code":1415,"language":1141,"meta":1142,"style":1142},"\u002F\u002F never do this blind — this is a NullPointerException with extra steps\nPose2d uncheckedPose = visionPose.get();\n",[1089,1417,1418,1423],{"__ignoreMap":1142},[1146,1419,1420],{"class":1148,"line":1149},[1146,1421,1422],{},"\u002F\u002F never do this blind — this is a NullPointerException with extra steps\n",[1146,1424,1425],{"class":1148,"line":1155},[1146,1426,1427],{},"Pose2d uncheckedPose = visionPose.get();\n",[1085,1429,1430,1431,1433,1434,1436,1437,1439,1440,1442,1443,1445,1446,1448],{},"Even the safer ",[1089,1432,1392],{}," + ",[1089,1435,1396],{}," pairing is discouraged — it's really just a nested-null-check in disguise. ",[1089,1438,1326],{},", ",[1089,1441,1330],{},", and ",[1089,1444,1334],{}," all handle both cases directly, without ever needing to call bare ",[1089,1447,1396],{},".",[1080,1450,1452],{"id":1451},"filtering-and-transforming-a-brief-look","Filtering and Transforming (a Brief Look)",[1085,1454,1455,1456,1458,1459,1462,1463,1466,1467,1470],{},"Beyond the core methods above, ",[1089,1457,1338],{}," supports ",[1089,1460,1461],{},"filter"," (keep the value only if it matches a condition, otherwise become empty) and ",[1089,1464,1465],{},"map"," (transform the value, if present, into something else) — useful for chaining a couple of extra checks without falling back into nested ",[1089,1468,1469],{},"if"," statements:",[1137,1472,1474],{"className":1139,"code":1473,"language":1141,"meta":1142,"style":1142},"visionPose\n    \u002F\u002F only proceed if the pose has a valid X coordinate\n    .filter(pose -> pose.getX() >= 0)\n    .ifPresent(pose -> estimator.addVisionMeasurement(pose, timestamp));\n",[1089,1475,1476,1481,1486,1491],{"__ignoreMap":1142},[1146,1477,1478],{"class":1148,"line":1149},[1146,1479,1480],{},"visionPose\n",[1146,1482,1483],{"class":1148,"line":1155},[1146,1484,1485],{},"    \u002F\u002F only proceed if the pose has a valid X coordinate\n",[1146,1487,1488],{"class":1148,"line":1161},[1146,1489,1490],{},"    .filter(pose -> pose.getX() >= 0)\n",[1146,1492,1493],{"class":1148,"line":1167},[1146,1494,1495],{},"    .ifPresent(pose -> estimator.addVisionMeasurement(pose, timestamp));\n",[1085,1497,1498,1500,1501,1503,1504,1506,1507,1509],{},[1089,1499,1465],{}," transforms the value inside an ",[1089,1502,1338],{},", without ever having to check ",[1089,1505,1392],{}," first — on an empty ",[1089,1508,1338],{},", it just stays empty:",[1137,1511,1513],{"className":1139,"code":1512,"language":1141,"meta":1142,"style":1142},"double dashboardX = visionPose.map(pose -> pose.getX()).orElse(0.0);\n",[1089,1514,1515],{"__ignoreMap":1142},[1146,1516,1517],{"class":1148,"line":1149},[1146,1518,1512],{},[1085,1520,1521,1524,1525,1528,1529,1532,1533,1536,1537,1540,1541,1544],{},[1089,1522,1523],{},"visionPose.map(pose -> pose.getX())"," turns an ",[1089,1526,1527],{},"Optional\u003CPose2d>"," into an ",[1089,1530,1531],{},"Optional\u003CDouble>"," — present with the X coordinate if ",[1089,1534,1535],{},"visionPose"," had a value, empty otherwise — and ",[1089,1538,1539],{},".orElse(0.0)"," then unwraps that down to a plain ",[1089,1542,1543],{},"double"," either way.",[1085,1546,1547,1548,1550],{},"These compose well for simple cases; genuinely complex chains of ",[1089,1549,1338],{}," transformations are a more advanced topic than this curriculum covers in depth.",[1080,1552,1554],{"id":1553},"common-pitfalls","Common Pitfalls",[1556,1557,1558,1572,1585],"ul",{},[1559,1560,1561,1568,1569,1571],"li",{},[1129,1562,1563,1564,1567],{},"Calling ",[1089,1565,1566],{},".get()"," without checking first."," This throws on an empty ",[1089,1570,1338],{},", defeating the entire purpose of using one.",[1559,1573,1574,1580,1581,1584],{},[1129,1575,1576,1577,1579],{},"Using ",[1089,1578,1338],{}," for every field or parameter, out of habit."," It's meant for genuinely optional ",[1111,1582,1583],{},"results"," (especially return values) — not a blanket replacement for every reference type in a program.",[1559,1586,1587,1595,1596,1599,1600,1448],{},[1129,1588,1589,1590,1592,1593,1448],{},"Passing a ",[1089,1591,1091],{}," to ",[1089,1594,1250],{}," That throws immediately — use ",[1089,1597,1598],{},"Optional.ofNullable(...)"," instead when the value genuinely might be ",[1089,1601,1091],{},[1080,1603,1605],{"id":1604},"key-takeaways","Key Takeaways",[1556,1607,1608,1617,1635,1651,1662],{},[1559,1609,1610,1613,1614,1616],{},[1089,1611,1612],{},"Optional\u003CT>"," makes \"this might not have a value\" visible directly in a method's return type, instead of relying on an invisible, easy-to-forget ",[1089,1615,1091],{}," check.",[1559,1618,1619,1620,1439,1623,1626,1627,1630,1631,1634],{},"Create one with ",[1089,1621,1622],{},"Optional.empty()",[1089,1624,1625],{},"Optional.of(value)"," (throws if ",[1089,1628,1629],{},"value"," is null), or ",[1089,1632,1633],{},"Optional.ofNullable(value)"," (safe either way).",[1559,1636,1637,1638,1439,1641,1644,1645,1648,1649,1567],{},"Handle both cases with ",[1089,1639,1640],{},"ifPresent(...)",[1089,1642,1643],{},"orElse(fallback)",", or ",[1089,1646,1647],{},"orElseThrow(...)"," — never call bare ",[1089,1650,1566],{},[1559,1652,1653,1655,1656,1658,1659,1661],{},[1089,1654,1461],{}," and ",[1089,1657,1465],{}," let you chain a couple of extra conditions\u002Ftransformations without falling back into nested ",[1089,1660,1469],{}," checks.",[1559,1663,1664,1665,1439,1667,1669,1670,1672,1673,1675],{},"Beyond the core methods: a no-argument ",[1089,1666,1361],{},[1089,1668,1369],{}," (lazy, unlike eager ",[1089,1671,1330],{},"), and ",[1089,1674,1376],{}," (a present\u002Fempty pair of callbacks) cover the less common cases.",[1085,1677,1678,1679,1682,1683,1686,1687,1690],{},"Derived from ",[1089,1680,1681],{},"other-reference-repo",": ",[1089,1684,1685],{},"oracle-java-tutorials\u002Foptional\u002Fjava8-optional.md"," (ORACLE 16.1)\n",[1129,1688,1689],{},"Deck context:"," mechacoder-test\u002Fsrc\u002Flessons\u002Fjava-2.js, slide 9b (\"Optional: Maybe a Value\") — vision pose estimator example",[1692,1693,1694],"style",{},"html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":1142,"searchDepth":1155,"depth":1155,"links":1696},[1697,1698,1699,1700,1701,1702,1703,1704],{"id":1082,"depth":1155,"text":1083},{"id":1120,"depth":1155,"text":1121},{"id":1204,"depth":1155,"text":1205},{"id":1260,"depth":1155,"text":1261},{"id":1383,"depth":1155,"text":1384},{"id":1451,"depth":1155,"text":1452},{"id":1553,"depth":1155,"text":1554},{"id":1604,"depth":1155,"text":1605},"md",{"outlineRef":1707,"status":1708},"24 — Optional: Avoiding Null Pointer Exceptions (ORACLE 16.1) — renamed from \"Optional: Maybe a Value\" to disambiguate from optional method parameters; the deck's actual slide heading is unchanged","new — authored lesson (fuller depth than the teaser slide)",{"title":266,"description":1142},"ClnAIgLcYqtgKZQYJbJDRFKtCmNYE2BBtKltjPLqKNM",{"id":1712,"title":699,"body":1713,"description":1142,"extension":1705,"meta":2322,"navigation":1220,"path":698,"seo":2325,"stem":700,"__hash__":2326},"examples\u002Fshockwave-curriculum\u002Fexamples\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions.md",{"type":1073,"value":1714,"toc":2309},[1715,1718,1722,1725,1729,1765,1769,1825,1894,1906,1910,1939,1956,1962,1991,2017,2021,2188,2192,2200,2215,2222,2228,2237,2256,2260,2307],[1076,1716,699],{"id":1717},"optional-avoiding-null-pointer-exceptions-worked-example",[1080,1719,1721],{"id":1720},"problem","Problem",[1085,1723,1724],{},"The robot logs motor temperatures for each mechanism. Write a method that finds the first temperature above a limit. Sometimes nothing is over the limit, so the method's return type should make it obvious that there might be no result. Then use it on two mechanisms: print a warning only for a mechanism that actually has an over-limit reading, and give the dashboard a number to display either way.",[1080,1726,1728],{"id":1727},"step-1-plan-it-first","Step 1: Plan It First",[1730,1731,1732,1744,1753,1756],"ol",{},[1559,1733,1734,1735,1738,1739,1741,1742,1448],{},"Write ",[1089,1736,1737],{},"firstOverLimit",", returning ",[1089,1740,1531],{}," instead of a plain ",[1089,1743,1543],{},[1559,1745,1746,1747,1749,1750,1752],{},"Inside it, return ",[1089,1748,1250],{}," when a reading is found, and ",[1089,1751,1622],{}," when none is.",[1559,1754,1755],{},"Call it for the drivetrain (which has a hot motor) and the intake (which doesn't).",[1559,1757,1758,1759,1761,1762,1764],{},"Handle the results with ",[1089,1760,1326],{}," (warn only if there's a value) and ",[1089,1763,1330],{}," (always get a number).",[1080,1766,1768],{"id":1767},"step-2-put-might-be-absent-in-the-return-type","Step 2: Put \"Might Be Absent\" in the Return Type",[1137,1770,1772],{"className":1139,"code":1771,"language":1141,"meta":1142,"style":1142},"public static Optional\u003CDouble> firstOverLimit(double[] temps, double limit)\n{\n    for (double t : temps)\n    {\n        if (t > limit)\n        {\n            return Optional.of(t);\n        }\n    }\n    return Optional.empty();\n}\n",[1089,1773,1774,1779,1783,1788,1792,1797,1802,1807,1812,1816,1821],{"__ignoreMap":1142},[1146,1775,1776],{"class":1148,"line":1149},[1146,1777,1778],{},"public static Optional\u003CDouble> firstOverLimit(double[] temps, double limit)\n",[1146,1780,1781],{"class":1148,"line":1155},[1146,1782,1158],{},[1146,1784,1785],{"class":1148,"line":1161},[1146,1786,1787],{},"    for (double t : temps)\n",[1146,1789,1790],{"class":1148,"line":1167},[1146,1791,1170],{},[1146,1793,1794],{"class":1148,"line":1173},[1146,1795,1796],{},"        if (t > limit)\n",[1146,1798,1799],{"class":1148,"line":1179},[1146,1800,1801],{},"        {\n",[1146,1803,1804],{"class":1148,"line":1185},[1146,1805,1806],{},"            return Optional.of(t);\n",[1146,1808,1809],{"class":1148,"line":1191},[1146,1810,1811],{},"        }\n",[1146,1813,1814],{"class":1148,"line":1306},[1146,1815,1182],{},[1146,1817,1818],{"class":1148,"line":1312},[1146,1819,1820],{},"    return Optional.empty();\n",[1146,1822,1823],{"class":1148,"line":1318},[1146,1824,1194],{},[1556,1826,1827,1833,1851,1859],{},[1559,1828,1829,1830,1832],{},"The signature says ",[1089,1831,1531],{},", so anyone calling it knows from the type alone that there might not be an answer.",[1559,1834,1835,1836,1839,1840,1843,1844,1846,1847,1850],{},"The loop is the same \"find the first match\" traversal from Ch.9. The moment a reading is over the limit, it's wrapped with ",[1089,1837,1838],{},"Optional.of(t)"," and returned. ",[1089,1841,1842],{},"t"," is a real number here, never ",[1089,1845,1091],{},", so ",[1089,1848,1849],{},"of"," is the right choice.",[1559,1852,1853,1854,1856,1857,1448],{},"If the loop finishes without finding one, the method returns ",[1089,1855,1622],{},". That means \"no value,\" and it isn't ",[1089,1858,1091],{},[1559,1860,1861,1863,1864,1866,1867,1870,1871,1874,1875,1655,1878,1881,1882,1884,1885,1887,1888,1890,1891,1893],{},[1089,1862,1531],{}," relies on the same autoboxing from Lesson 9.2 to wrap a ",[1089,1865,1543],{}," as a ",[1089,1868,1869],{},"Double",". Java also has a specialized ",[1089,1872,1873],{},"OptionalDouble"," (plus ",[1089,1876,1877],{},"OptionalInt",[1089,1879,1880],{},"OptionalLong",") that skips the boxing — this example sticks with ",[1089,1883,1531],{}," since it composes with ",[1089,1886,1326],{},"\u002F",[1089,1889,1330],{}," exactly like every other ",[1089,1892,1612],{}," in this lesson.",[1085,1895,1896,1898,1899,1902,1903,1448],{},[1089,1897,1338],{}," lives in ",[1089,1900,1901],{},"java.util",", so the file needs ",[1089,1904,1905],{},"import java.util.Optional;",[1080,1907,1909],{"id":1908},"step-3-call-it-for-two-mechanisms","Step 3: Call It for Two Mechanisms",[1137,1911,1913],{"className":1139,"code":1912,"language":1141,"meta":1142,"style":1142},"double[] drivetrainTemps = {41.5, 38.0, 72.5, 44.0};\ndouble[] intakeTemps = {35.0, 36.5};\n\nOptional\u003CDouble> drivetrainHot = firstOverLimit(drivetrainTemps, 70.0);\nOptional\u003CDouble> intakeHot = firstOverLimit(intakeTemps, 70.0);\n",[1089,1914,1915,1920,1925,1929,1934],{"__ignoreMap":1142},[1146,1916,1917],{"class":1148,"line":1149},[1146,1918,1919],{},"double[] drivetrainTemps = {41.5, 38.0, 72.5, 44.0};\n",[1146,1921,1922],{"class":1148,"line":1155},[1146,1923,1924],{},"double[] intakeTemps = {35.0, 36.5};\n",[1146,1926,1927],{"class":1148,"line":1161},[1146,1928,1221],{"emptyLinePlaceholder":1220},[1146,1930,1931],{"class":1148,"line":1167},[1146,1932,1933],{},"Optional\u003CDouble> drivetrainHot = firstOverLimit(drivetrainTemps, 70.0);\n",[1146,1935,1936],{"class":1148,"line":1173},[1146,1937,1938],{},"Optional\u003CDouble> intakeHot = firstOverLimit(intakeTemps, 70.0);\n",[1085,1940,1941,1944,1945,1948,1949,1952,1953,1448],{},[1089,1942,1943],{},"drivetrainHot"," holds ",[1089,1946,1947],{},"72.5",". ",[1089,1950,1951],{},"intakeHot"," is empty, since neither intake reading is over ",[1089,1954,1955],{},"70.0",[1080,1957,1959,1960],{"id":1958},"step-4-handle-both-cases-without-get","Step 4: Handle Both Cases Without ",[1089,1961,1396],{},[1137,1963,1965],{"className":1139,"code":1964,"language":1141,"meta":1142,"style":1142},"drivetrainHot.ifPresent(t -> System.out.println(\"Drivetrain warning: \" + t + \" C\"));\nintakeHot.ifPresent(t -> System.out.println(\"Intake warning: \" + t + \" C\"));\n\ndouble intakeDashboard = intakeHot.orElse(0.0);\nSystem.out.println(\"Intake over-limit reading for the dashboard: \" + intakeDashboard);\n",[1089,1966,1967,1972,1977,1981,1986],{"__ignoreMap":1142},[1146,1968,1969],{"class":1148,"line":1149},[1146,1970,1971],{},"drivetrainHot.ifPresent(t -> System.out.println(\"Drivetrain warning: \" + t + \" C\"));\n",[1146,1973,1974],{"class":1148,"line":1155},[1146,1975,1976],{},"intakeHot.ifPresent(t -> System.out.println(\"Intake warning: \" + t + \" C\"));\n",[1146,1978,1979],{"class":1148,"line":1161},[1146,1980,1221],{"emptyLinePlaceholder":1220},[1146,1982,1983],{"class":1148,"line":1167},[1146,1984,1985],{},"double intakeDashboard = intakeHot.orElse(0.0);\n",[1146,1987,1988],{"class":1148,"line":1173},[1146,1989,1990],{},"System.out.println(\"Intake over-limit reading for the dashboard: \" + intakeDashboard);\n",[1556,1992,1993,2003],{},[1559,1994,1995,1997,1998,2000,2001,1616],{},[1089,1996,1326],{}," runs its lambda (Lesson 19.1) only when there's a value. The drivetrain line prints a warning. The intake line does nothing at all, with no ",[1089,1999,1469],{}," and no ",[1089,2002,1091],{},[1559,2004,2005,2006,2009,2010,2013,2014,1448],{},"The dashboard needs ",[1111,2007,2008],{},"some"," number every time, so ",[1089,2011,2012],{},"orElse(0.0)"," supplies one: the real reading if there is one, otherwise ",[1089,2015,2016],{},"0.0",[1080,2018,2020],{"id":2019},"step-5-the-whole-program","Step 5: The Whole Program",[1137,2022,2024],{"className":1139,"code":2023,"language":1141,"meta":1142,"style":1142},"import java.util.Optional;\n\npublic class MotorTempCheck\n{\n    public static Optional\u003CDouble> firstOverLimit(double[] temps, double limit)\n    {\n        for (double t : temps)\n        {\n            if (t > limit)\n            {\n                return Optional.of(t);\n            }\n        }\n        return Optional.empty();\n    }\n\n    public static void main(String[] args)\n    {\n        double[] drivetrainTemps = {41.5, 38.0, 72.5, 44.0};\n        double[] intakeTemps = {35.0, 36.5};\n\n        Optional\u003CDouble> drivetrainHot = firstOverLimit(drivetrainTemps, 70.0);\n        Optional\u003CDouble> intakeHot = firstOverLimit(intakeTemps, 70.0);\n\n        drivetrainHot.ifPresent(t -> System.out.println(\"Drivetrain warning: \" + t + \" C\"));\n        intakeHot.ifPresent(t -> System.out.println(\"Intake warning: \" + t + \" C\"));\n\n        double intakeDashboard = intakeHot.orElse(0.0);\n        System.out.println(\"Intake over-limit reading for the dashboard: \" + intakeDashboard);\n    }\n}\n",[1089,2025,2026,2031,2035,2040,2044,2049,2053,2058,2062,2067,2072,2077,2083,2088,2094,2099,2104,2110,2115,2121,2127,2132,2138,2144,2149,2155,2161,2166,2172,2178,2183],{"__ignoreMap":1142},[1146,2027,2028],{"class":1148,"line":1149},[1146,2029,2030],{},"import java.util.Optional;\n",[1146,2032,2033],{"class":1148,"line":1155},[1146,2034,1221],{"emptyLinePlaceholder":1220},[1146,2036,2037],{"class":1148,"line":1161},[1146,2038,2039],{},"public class MotorTempCheck\n",[1146,2041,2042],{"class":1148,"line":1167},[1146,2043,1158],{},[1146,2045,2046],{"class":1148,"line":1173},[1146,2047,2048],{},"    public static Optional\u003CDouble> firstOverLimit(double[] temps, double limit)\n",[1146,2050,2051],{"class":1148,"line":1179},[1146,2052,1170],{},[1146,2054,2055],{"class":1148,"line":1185},[1146,2056,2057],{},"        for (double t : temps)\n",[1146,2059,2060],{"class":1148,"line":1191},[1146,2061,1801],{},[1146,2063,2064],{"class":1148,"line":1306},[1146,2065,2066],{},"            if (t > limit)\n",[1146,2068,2069],{"class":1148,"line":1312},[1146,2070,2071],{},"            {\n",[1146,2073,2074],{"class":1148,"line":1318},[1146,2075,2076],{},"                return Optional.of(t);\n",[1146,2078,2080],{"class":1148,"line":2079},12,[1146,2081,2082],{},"            }\n",[1146,2084,2086],{"class":1148,"line":2085},13,[1146,2087,1811],{},[1146,2089,2091],{"class":1148,"line":2090},14,[1146,2092,2093],{},"        return Optional.empty();\n",[1146,2095,2097],{"class":1148,"line":2096},15,[1146,2098,1182],{},[1146,2100,2102],{"class":1148,"line":2101},16,[1146,2103,1221],{"emptyLinePlaceholder":1220},[1146,2105,2107],{"class":1148,"line":2106},17,[1146,2108,2109],{},"    public static void main(String[] args)\n",[1146,2111,2113],{"class":1148,"line":2112},18,[1146,2114,1170],{},[1146,2116,2118],{"class":1148,"line":2117},19,[1146,2119,2120],{},"        double[] drivetrainTemps = {41.5, 38.0, 72.5, 44.0};\n",[1146,2122,2124],{"class":1148,"line":2123},20,[1146,2125,2126],{},"        double[] intakeTemps = {35.0, 36.5};\n",[1146,2128,2130],{"class":1148,"line":2129},21,[1146,2131,1221],{"emptyLinePlaceholder":1220},[1146,2133,2135],{"class":1148,"line":2134},22,[1146,2136,2137],{},"        Optional\u003CDouble> drivetrainHot = firstOverLimit(drivetrainTemps, 70.0);\n",[1146,2139,2141],{"class":1148,"line":2140},23,[1146,2142,2143],{},"        Optional\u003CDouble> intakeHot = firstOverLimit(intakeTemps, 70.0);\n",[1146,2145,2147],{"class":1148,"line":2146},24,[1146,2148,1221],{"emptyLinePlaceholder":1220},[1146,2150,2152],{"class":1148,"line":2151},25,[1146,2153,2154],{},"        drivetrainHot.ifPresent(t -> System.out.println(\"Drivetrain warning: \" + t + \" C\"));\n",[1146,2156,2158],{"class":1148,"line":2157},26,[1146,2159,2160],{},"        intakeHot.ifPresent(t -> System.out.println(\"Intake warning: \" + t + \" C\"));\n",[1146,2162,2164],{"class":1148,"line":2163},27,[1146,2165,1221],{"emptyLinePlaceholder":1220},[1146,2167,2169],{"class":1148,"line":2168},28,[1146,2170,2171],{},"        double intakeDashboard = intakeHot.orElse(0.0);\n",[1146,2173,2175],{"class":1148,"line":2174},29,[1146,2176,2177],{},"        System.out.println(\"Intake over-limit reading for the dashboard: \" + intakeDashboard);\n",[1146,2179,2181],{"class":1148,"line":2180},30,[1146,2182,1182],{},[1146,2184,2186],{"class":1148,"line":2185},31,[1146,2187,1194],{},[1080,2189,2191],{"id":2190},"what-it-prints","What It Prints",[1137,2193,2198],{"className":2194,"code":2196,"language":2197},[2195],"language-text","Drivetrain warning: 72.5 C\nIntake over-limit reading for the dashboard: 0.0\n","text",[1089,2199,2196],{"__ignoreMap":1142},[1085,2201,2202,2203,2205,2206,2208,2209,2211,2212,2214],{},"There's only one warning line. The intake's ",[1089,2204,1326],{}," had nothing to run on, so it printed nothing. The intake's ",[1089,2207,1330],{}," fell back to ",[1089,2210,2016],{}," because its ",[1089,2213,1338],{}," was empty.",[1080,2216,2218,2219,2221],{"id":2217},"what-calling-get-blind-would-look-like","What Calling ",[1089,2220,1396],{}," Blind Would Look Like",[1085,2223,2224,2225,2227],{},"Say the ",[1089,2226,1330],{}," line were replaced with:",[1137,2229,2231],{"className":1139,"code":2230,"language":1141,"meta":1142,"style":1142},"double intakeDashboard = intakeHot.get();\n",[1089,2232,2233],{"__ignoreMap":1142},[1146,2234,2235],{"class":1148,"line":1149},[1146,2236,2230],{},[1085,2238,2239,2240,2242,2243,2246,2247,2249,2250,2252,2253,2255],{},"This compiles, but ",[1089,2241,1951],{}," is empty, so the program prints the drivetrain warning and then crashes with ",[1089,2244,2245],{},"java.util.NoSuchElementException: No value present",". That's the lesson's warning in action: a blind ",[1089,2248,1396],{}," brings back the exact crash ",[1089,2251,1338],{}," was supposed to prevent, just with a different exception name. ",[1089,2254,1330],{}," handles the empty case without ever risking it.",[1080,2257,2259],{"id":2258},"recap","Recap",[1556,2261,2262,2268,2278,2287,2292],{},[1559,2263,2264,2265,2267],{},"A method that might not have a result can return ",[1089,2266,1612],{},", so the possibility is written into its return type.",[1559,2269,2270,2272,2273,2275,2276,1448],{},[1089,2271,1625],{}," wraps a real, non-null value. ",[1089,2274,1622],{}," means \"no value,\" instead of returning ",[1089,2277,1091],{},[1559,2279,2280,2283,2284,2286],{},[1089,2281,2282],{},"ifPresent(lambda)"," runs code only when a value is there. On an empty ",[1089,2285,1338],{},", it does nothing.",[1559,2288,2289,2291],{},[1089,2290,1643],{}," always produces a value: the real one if present, the fallback otherwise.",[1559,2293,1563,2294,1406,2296,2298,2299,2301,2302,1887,2304,2306],{},[1089,2295,1396],{},[1089,2297,1338],{}," throws ",[1089,2300,1365],{},". Use ",[1089,2303,1326],{},[1089,2305,1330],{}," instead.",[1692,2308,1694],{},{"title":1142,"searchDepth":1155,"depth":1155,"links":2310},[2311,2312,2313,2314,2315,2317,2318,2319,2321],{"id":1720,"depth":1155,"text":1721},{"id":1727,"depth":1155,"text":1728},{"id":1767,"depth":1155,"text":1768},{"id":1908,"depth":1155,"text":1909},{"id":1958,"depth":1155,"text":2316},"Step 4: Handle Both Cases Without get()",{"id":2019,"depth":1155,"text":2020},{"id":2190,"depth":1155,"text":2191},{"id":2217,"depth":1155,"text":2320},"What Calling get() Blind Would Look Like",{"id":2258,"depth":1155,"text":2259},{"outlineRef":1707,"pairsWith":2323,"status":2324},"[`lessons\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions.md`](..\u002F..\u002Flessons\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions.md)","new — authored worked example (fully solved, walked step by step — not a problem to attempt)",{"title":699,"description":1142},"fx1xXxc-LQAzPxRU87sg9NVwslCdKDrhmqwO7gPZHa8",{"id":2328,"title":1012,"body":2329,"description":1142,"extension":1705,"meta":3590,"navigation":1220,"path":1011,"seo":3592,"stem":1013,"__hash__":3593},"exercises\u002Fshockwave-curriculum\u002Fexercises\u002Fch24-optional-avoiding-null-pointer-exceptions\u002F24-optional-avoiding-null-pointer-exceptions.md",{"type":1073,"value":2330,"toc":3585},[2331,2334,2338,2347,2362,2367,2391,2397,2418,2470,2474,2501,2504,2571,2576,2582,2640,2741,2745,2751,2773,2834,2848,2853,3056,3061,3066,3072,3077,3083,3088,3092,3098,3102,3108,3113,3117,3123,3127,3133,3138,3142,3148,3152,3158,3163,3167,3173,3177,3183,3188,3192,3198,3202,3208,3213,3534,3583],[1076,2332,1012],{"id":2333},"optional-avoiding-null-pointer-exceptions-exercises",[1080,2335,2337],{"id":2336},"multiple-choice","Multiple Choice",[1085,2339,2340,2343,2344,2346],{},[1129,2341,2342],{},"Question:"," No alliance color has been reported yet, so a method returned an empty ",[1089,2345,1338],{},". What does this code print?",[1137,2348,2350],{"className":1139,"code":2349,"language":1141,"meta":1142,"style":1142},"Optional\u003CString> alliance = Optional.empty();\nSystem.out.println(alliance.orElse(\"Unknown\"));\n",[1089,2351,2352,2357],{"__ignoreMap":1142},[1146,2353,2354],{"class":1148,"line":1149},[1146,2355,2356],{},"Optional\u003CString> alliance = Optional.empty();\n",[1146,2358,2359],{"class":1148,"line":1155},[1146,2360,2361],{},"System.out.println(alliance.orElse(\"Unknown\"));\n",[1085,2363,2364],{},[1129,2365,2366],{},"Options:",[1556,2368,2369,2375,2380,2385],{},[1559,2370,2371,2372],{},"A. ",[1089,2373,2374],{},"Unknown",[1559,2376,2377,2378],{},"B. ",[1089,2379,1091],{},[1559,2381,2382,2383],{},"C. Nothing prints. It throws ",[1089,2384,1365],{},[1559,2386,2387,2388],{},"D. ",[1089,2389,2390],{},"Optional.empty",[1085,2392,2393,2396],{},[1129,2394,2395],{},"Answer:"," A",[1085,2398,2399,2402,2403,2405,2406,2409,2410,2413,2414,2417],{},[1129,2400,2401],{},"Why:"," ",[1089,2404,1330],{}," returns the wrapped value if there is one, and otherwise the fallback it was given. ",[1089,2407,2408],{},"alliance"," is empty, so ",[1089,2411,2412],{},"orElse(\"Unknown\")"," returns ",[1089,2415,2416],{},"\"Unknown\"",", and that's what prints.",[1556,2419,2420,2434,2447],{},[1559,2421,2422,2423,2425,2426,1442,2428,2430,2431,2433],{},"B is wrong. An empty ",[1089,2424,1338],{}," isn't ",[1089,2427,1091],{},[1089,2429,1330],{}," never hands back a ",[1089,2432,1091],{}," in place of the fallback. The fallback is the whole point.",[1559,2435,2436,2437,2439,2440,1406,2442,1948,2444,2446],{},"C is wrong. ",[1089,2438,1365],{}," comes from calling bare ",[1089,2441,1396],{},[1089,2443,1338],{},[1089,2445,1330],{}," handles the empty case safely instead of throwing.",[1559,2448,2449,2450,2452,2453,2455,2456,2459,2460,2463,2464,2466,2467,1448],{},"D is wrong. ",[1089,2451,2390],{}," is what you'd see from printing the ",[1089,2454,1338],{}," object ",[1111,2457,2458],{},"itself"," (",[1089,2461,2462],{},"System.out.println(alliance)","). Here, ",[1089,2465,1330],{}," unwraps it first, so what prints is a ",[1089,2468,2469],{},"String",[1080,2471,2473],{"id":2472},"micro-parsons","Micro-Parsons",[1085,2475,2476,2479,2480,2483,2484,2486,2487,2489,2490,2493,2494,2497,2498,1448],{},[1129,2477,2478],{},"Problem:"," These lines, once correctly ordered, form a complete program. The driver hasn't picked an autonomous routine yet, so ",[1089,2481,2482],{},"chosenAuto"," is ",[1089,2485,1091],{}," (a stand-in for a real driver-station selection). The program safely wraps it in an ",[1089,2488,1338],{},", prints ",[1089,2491,2492],{},"Running \u003Cname>"," only if a routine was chosen, and always prints which routine is selected, falling back to ",[1089,2495,2496],{},"\"None\"",". Right now it prints ",[1089,2499,2500],{},"Selected: None",[1085,2502,2503],{},"Reorder the fragments below into a working program:",[1556,2505,2506,2512,2518,2524,2530,2536,2542,2548,2553,2559,2565],{},[1559,2507,2508,2509],{},"a. ",[1089,2510,2511],{},"        auto.ifPresent(name -> System.out.println(\"Running \" + name));",[1559,2513,2514,2515],{},"b. ",[1089,2516,2517],{},"    public static void main(String[] args)",[1559,2519,2520,2521],{},"c. ",[1089,2522,2523],{},"}",[1559,2525,2526,2527],{},"d. ",[1089,2528,2529],{},"        Optional\u003CString> auto = Optional.ofNullable(chosenAuto);",[1559,2531,2532,2533],{},"e. ",[1089,2534,2535],{},"public class AutoSelection",[1559,2537,2538,2539],{},"f. ",[1089,2540,2541],{},"    }",[1559,2543,2544,2545],{},"g. ",[1089,2546,2547],{},"        String chosenAuto = null;",[1559,2549,2550,2551],{},"h. ",[1089,2552,1905],{},[1559,2554,2555,2556],{},"i. ",[1089,2557,2558],{},"        System.out.println(\"Selected: \" + auto.orElse(\"None\"));",[1559,2560,2561,2562],{},"j. ",[1089,2563,2564],{},"    {",[1559,2566,2567,2568],{},"k. ",[1089,2569,2570],{},"{",[1085,2572,2573,2575],{},[1129,2574,2395],{}," h, e, k, b, j, g, d, a, i, f, c",[1085,2577,2578,2581],{},[1129,2579,2580],{},"Interchangeable:"," (a, i)",[1137,2583,2585],{"className":1139,"code":2584,"language":1141,"meta":1142,"style":1142},"import java.util.Optional;\n\npublic class AutoSelection\n{\n    public static void main(String[] args)\n    {\n        String chosenAuto = null;\n        Optional\u003CString> auto = Optional.ofNullable(chosenAuto);\n        auto.ifPresent(name -> System.out.println(\"Running \" + name));\n        System.out.println(\"Selected: \" + auto.orElse(\"None\"));\n    }\n}\n",[1089,2586,2587,2591,2595,2600,2604,2608,2612,2617,2622,2627,2632,2636],{"__ignoreMap":1142},[1146,2588,2589],{"class":1148,"line":1149},[1146,2590,2030],{},[1146,2592,2593],{"class":1148,"line":1155},[1146,2594,1221],{"emptyLinePlaceholder":1220},[1146,2596,2597],{"class":1148,"line":1161},[1146,2598,2599],{},"public class AutoSelection\n",[1146,2601,2602],{"class":1148,"line":1167},[1146,2603,1158],{},[1146,2605,2606],{"class":1148,"line":1173},[1146,2607,2109],{},[1146,2609,2610],{"class":1148,"line":1179},[1146,2611,1170],{},[1146,2613,2614],{"class":1148,"line":1185},[1146,2615,2616],{},"        String chosenAuto = null;\n",[1146,2618,2619],{"class":1148,"line":1191},[1146,2620,2621],{},"        Optional\u003CString> auto = Optional.ofNullable(chosenAuto);\n",[1146,2623,2624],{"class":1148,"line":1306},[1146,2625,2626],{},"        auto.ifPresent(name -> System.out.println(\"Running \" + name));\n",[1146,2628,2629],{"class":1148,"line":1312},[1146,2630,2631],{},"        System.out.println(\"Selected: \" + auto.orElse(\"None\"));\n",[1146,2633,2634],{"class":1148,"line":1318},[1146,2635,1182],{},[1146,2637,2638],{"class":1148,"line":2079},[1146,2639,1194],{},[1085,2641,2642,2645,2646,2459,2649,2652,2653,2655,2656,2659,2660,1439,2663,1439,2666,1439,2669,2672,2673,2459,2675,2678,2679,2459,2682,2685,2686,1948,2688,2691,2692,2694,2695,2459,2698,1655,2701,2704,2705,2707,2708,2710,2711,2713,2714,2716,2717,2719,2720,2722,2723,2726,2727,2729,2730,2732,2733,2736,2737,2740],{},[1129,2643,2644],{},"Why this order:"," The ",[1089,2647,2648],{},"import",[1089,2650,2651],{},"h",") has to come before the class that uses ",[1089,2654,1338],{},". Then come the usual class and ",[1089,2657,2658],{},"main"," lines (",[1089,2661,2662],{},"e",[1089,2664,2665],{},"k",[1089,2667,2668],{},"b",[1089,2670,2671],{},"j","). ",[1089,2674,2482],{},[1089,2676,2677],{},"g",") has to exist before it can be wrapped. ",[1089,2680,2681],{},"ofNullable",[1089,2683,2684],{},"d",") is the right way to wrap it, because it might be ",[1089,2687,1091],{},[1089,2689,2690],{},"Optional.of(chosenAuto)"," would throw immediately on a ",[1089,2693,1091],{},". Both uses of ",[1089,2696,2697],{},"auto",[1089,2699,2700],{},"a",[1089,2702,2703],{},"i",") have to come after it's created. They can go in either order (hence ",[1129,2706,2580],{}," (a, i)): ",[1089,2709,2697],{}," is empty here, so ",[1089,2712,1326],{}," does nothing, and the output is ",[1089,2715,2500],{}," either way. (That's specific to ",[1089,2718,2482],{}," being ",[1089,2721,1091],{}," in ",[1111,2724,2725],{},"this"," program — if a routine had actually been chosen, ",[1089,2728,1326],{}," would print a \"Running ...\" line, and swapping the two statements would change which line prints first. Both orders still print the same two lines either way, just in a different sequence.) The braces close in reverse: ",[1089,2731,2658],{},"'s body (",[1089,2734,2735],{},"f","), then the class's body (",[1089,2738,2739],{},"c",").",[1080,2742,2744],{"id":2743},"coding","Coding",[1085,2746,2747,2750],{},[1129,2748,2749],{},"Mode:"," full-program",[1085,2752,2753,2755,2756,2759,2760,2413,2763,2765,2766,2769,2770,2772],{},[1129,2754,2478],{}," A camera knows the distance to each AprilTag it can currently see, stored in a ",[1089,2757,2758],{},"Map\u003CInteger, Double>"," (a tag id the camera can't see is simply not in the map,\nso ",[1089,2761,2762],{},"map.get(id)",[1089,2764,1091],{},"). Write the class ",[1089,2767,2768],{},"Vision",", whose methods turn that into ",[1089,2771,1338],{}," results:",[1556,2774,2775,2781,2792,2802,2820],{},[1559,2776,2777,2780],{},[1089,2778,2779],{},"Vision(Map\u003CInteger, Double> distances)"," stores the map.",[1559,2782,2783,2786,2787,2402,2789,2791],{},[1089,2784,2785],{},"Optional\u003CDouble> getDistance(int id)"," returns the distance for that tag, or an ",[1129,2788,1131],{},[1089,2790,1338],{}," if the tag isn't in the map. It must never throw.",[1559,2793,2794,2797,2798,2801],{},[1089,2795,2796],{},"double distanceOrDefault(int id, double fallback)"," returns the distance, or ",[1089,2799,2800],{},"fallback"," if the tag isn't there.",[1559,2803,2804,2807,2808,2811,2812,2815,2816,2819],{},[1089,2805,2806],{},"double requireDistance(int id)"," returns the distance, or throws ",[1089,2809,2810],{},"IllegalStateException"," with the message ",[1089,2813,2814],{},"No tag "," followed by the id (for example ",[1089,2817,2818],{},"No tag 7",") if it isn't there.",[1559,2821,2822,2825,2826,2829,2830,2833],{},[1089,2823,2824],{},"Optional\u003CDouble> closeDistance(int id, double max)"," returns the distance only if the tag is seen ",[1129,2827,2828],{},"and"," its distance is at most ",[1089,2831,2832],{},"max"," (equal counts as close); otherwise empty.",[1085,2835,2836,2837,2839,2840,2842,2843,1948,2845,2847],{},"Do not call ",[1089,2838,1396],{}," or ",[1089,2841,1392],{}," on an ",[1089,2844,1338],{},[1089,2846,2658],{}," reads the tag table, then a list of tag ids to look up.",[1085,2849,2850],{},[1129,2851,2852],{},"Starter:",[1137,2854,2856],{"className":1139,"code":2855,"language":1141,"meta":1142,"style":1142},"import java.util.HashMap;\nimport java.util.Map;\nimport java.util.Optional;\nimport java.util.Scanner;\n\npublic class Main\n{\n    public static void main(String[] args) \u002F\u002F Don't change main\n    {\n        Scanner in = new Scanner(System.in);\n        int tagCount = in.nextInt();\n        Map\u003CInteger, Double> distances = new HashMap\u003C>();\n        for (int i = 0; i \u003C tagCount; i++)\n        {\n            int id = in.nextInt();\n            distances.put(id, in.nextDouble());\n        }\n        Vision vision = new Vision(distances);\n\n        int queries = in.nextInt();\n        for (int i = 0; i \u003C queries; i++)\n        {\n            int id = in.nextInt();\n            System.out.println(\"Tag \" + id);\n            Optional\u003CDouble> distance = vision.getDistance(id);\n            System.out.println(\"  seen: \" + distance.map(d -> \"distance \" + d).orElse(\"not seen\"));\n            System.out.println(\"  or default: \" + vision.distanceOrDefault(id, -1.0));\n            try\n            {\n                System.out.println(\"  required: \" + vision.requireDistance(id));\n            }\n            catch (IllegalStateException e)\n            {\n                System.out.println(\"  required: \" + e.getMessage());\n            }\n            vision.closeDistance(id, 3.0).ifPresent(d -> System.out.println(\"  close: \" + d));\n        }\n    }\n}\n\n\u002F\u002F TODO: write the class Vision\n",[1089,2857,2858,2863,2868,2872,2877,2881,2886,2890,2895,2899,2904,2909,2914,2919,2923,2928,2933,2937,2942,2946,2951,2956,2960,2964,2969,2974,2979,2984,2989,2993,2998,3002,3008,3013,3019,3024,3030,3035,3040,3045,3050],{"__ignoreMap":1142},[1146,2859,2860],{"class":1148,"line":1149},[1146,2861,2862],{},"import java.util.HashMap;\n",[1146,2864,2865],{"class":1148,"line":1155},[1146,2866,2867],{},"import java.util.Map;\n",[1146,2869,2870],{"class":1148,"line":1161},[1146,2871,2030],{},[1146,2873,2874],{"class":1148,"line":1167},[1146,2875,2876],{},"import java.util.Scanner;\n",[1146,2878,2879],{"class":1148,"line":1173},[1146,2880,1221],{"emptyLinePlaceholder":1220},[1146,2882,2883],{"class":1148,"line":1179},[1146,2884,2885],{},"public class Main\n",[1146,2887,2888],{"class":1148,"line":1185},[1146,2889,1158],{},[1146,2891,2892],{"class":1148,"line":1191},[1146,2893,2894],{},"    public static void main(String[] args) \u002F\u002F Don't change main\n",[1146,2896,2897],{"class":1148,"line":1306},[1146,2898,1170],{},[1146,2900,2901],{"class":1148,"line":1312},[1146,2902,2903],{},"        Scanner in = new Scanner(System.in);\n",[1146,2905,2906],{"class":1148,"line":1318},[1146,2907,2908],{},"        int tagCount = in.nextInt();\n",[1146,2910,2911],{"class":1148,"line":2079},[1146,2912,2913],{},"        Map\u003CInteger, Double> distances = new HashMap\u003C>();\n",[1146,2915,2916],{"class":1148,"line":2085},[1146,2917,2918],{},"        for (int i = 0; i \u003C tagCount; i++)\n",[1146,2920,2921],{"class":1148,"line":2090},[1146,2922,1801],{},[1146,2924,2925],{"class":1148,"line":2096},[1146,2926,2927],{},"            int id = in.nextInt();\n",[1146,2929,2930],{"class":1148,"line":2101},[1146,2931,2932],{},"            distances.put(id, in.nextDouble());\n",[1146,2934,2935],{"class":1148,"line":2106},[1146,2936,1811],{},[1146,2938,2939],{"class":1148,"line":2112},[1146,2940,2941],{},"        Vision vision = new Vision(distances);\n",[1146,2943,2944],{"class":1148,"line":2117},[1146,2945,1221],{"emptyLinePlaceholder":1220},[1146,2947,2948],{"class":1148,"line":2123},[1146,2949,2950],{},"        int queries = in.nextInt();\n",[1146,2952,2953],{"class":1148,"line":2129},[1146,2954,2955],{},"        for (int i = 0; i \u003C queries; i++)\n",[1146,2957,2958],{"class":1148,"line":2134},[1146,2959,1801],{},[1146,2961,2962],{"class":1148,"line":2140},[1146,2963,2927],{},[1146,2965,2966],{"class":1148,"line":2146},[1146,2967,2968],{},"            System.out.println(\"Tag \" + id);\n",[1146,2970,2971],{"class":1148,"line":2151},[1146,2972,2973],{},"            Optional\u003CDouble> distance = vision.getDistance(id);\n",[1146,2975,2976],{"class":1148,"line":2157},[1146,2977,2978],{},"            System.out.println(\"  seen: \" + distance.map(d -> \"distance \" + d).orElse(\"not seen\"));\n",[1146,2980,2981],{"class":1148,"line":2163},[1146,2982,2983],{},"            System.out.println(\"  or default: \" + vision.distanceOrDefault(id, -1.0));\n",[1146,2985,2986],{"class":1148,"line":2168},[1146,2987,2988],{},"            try\n",[1146,2990,2991],{"class":1148,"line":2174},[1146,2992,2071],{},[1146,2994,2995],{"class":1148,"line":2180},[1146,2996,2997],{},"                System.out.println(\"  required: \" + vision.requireDistance(id));\n",[1146,2999,3000],{"class":1148,"line":2185},[1146,3001,2082],{},[1146,3003,3005],{"class":1148,"line":3004},32,[1146,3006,3007],{},"            catch (IllegalStateException e)\n",[1146,3009,3011],{"class":1148,"line":3010},33,[1146,3012,2071],{},[1146,3014,3016],{"class":1148,"line":3015},34,[1146,3017,3018],{},"                System.out.println(\"  required: \" + e.getMessage());\n",[1146,3020,3022],{"class":1148,"line":3021},35,[1146,3023,2082],{},[1146,3025,3027],{"class":1148,"line":3026},36,[1146,3028,3029],{},"            vision.closeDistance(id, 3.0).ifPresent(d -> System.out.println(\"  close: \" + d));\n",[1146,3031,3033],{"class":1148,"line":3032},37,[1146,3034,1811],{},[1146,3036,3038],{"class":1148,"line":3037},38,[1146,3039,1182],{},[1146,3041,3043],{"class":1148,"line":3042},39,[1146,3044,1194],{},[1146,3046,3048],{"class":1148,"line":3047},40,[1146,3049,1221],{"emptyLinePlaceholder":1220},[1146,3051,3053],{"class":1148,"line":3052},41,[1146,3054,3055],{},"\u002F\u002F TODO: write the class Vision\n",[1085,3057,3058],{},[1129,3059,3060],{},"Scenario 1 (visible):",[1085,3062,3063],{},[1129,3064,3065],{},"Input:",[1137,3067,3070],{"className":3068,"code":3069,"language":2197,"meta":1142},[2195],"2\n1 2.5\n2 8.0\n2\n1\n2\n",[1089,3071,3069],{"__ignoreMap":1142},[1085,3073,3074],{},[1129,3075,3076],{},"Expected output:",[1137,3078,3081],{"className":3079,"code":3080,"language":2197,"meta":1142},[2195],"Tag 1\n  seen: distance 2.5\n  or default: 2.5\n  required: 2.5\n  close: 2.5\nTag 2\n  seen: distance 8.0\n  or default: 8.0\n  required: 8.0\n",[1089,3082,3080],{"__ignoreMap":1142},[1085,3084,3085],{},[1129,3086,3087],{},"Scenario 2 (visible):",[1085,3089,3090],{},[1129,3091,3065],{},[1137,3093,3096],{"className":3094,"code":3095,"language":2197,"meta":1142},[2195],"1\n5 3.0\n1\n9\n",[1089,3097,3095],{"__ignoreMap":1142},[1085,3099,3100],{},[1129,3101,3076],{},[1137,3103,3106],{"className":3104,"code":3105,"language":2197,"meta":1142},[2195],"Tag 9\n  seen: not seen\n  or default: -1.0\n  required: No tag 9\n",[1089,3107,3105],{"__ignoreMap":1142},[1085,3109,3110],{},[1129,3111,3112],{},"Scenario 3 (visible):",[1085,3114,3115],{},[1129,3116,3065],{},[1137,3118,3121],{"className":3119,"code":3120,"language":2197,"meta":1142},[2195],"0\n1\n4\n",[1089,3122,3120],{"__ignoreMap":1142},[1085,3124,3125],{},[1129,3126,3076],{},[1137,3128,3131],{"className":3129,"code":3130,"language":2197,"meta":1142},[2195],"Tag 4\n  seen: not seen\n  or default: -1.0\n  required: No tag 4\n",[1089,3132,3130],{"__ignoreMap":1142},[1085,3134,3135],{},[1129,3136,3137],{},"Scenario 4 (hidden):",[1085,3139,3140],{},[1129,3141,3065],{},[1137,3143,3146],{"className":3144,"code":3145,"language":2197,"meta":1142},[2195],"3\n10 3.0\n11 3.5\n12 0.5\n3\n10\n11\n12\n",[1089,3147,3145],{"__ignoreMap":1142},[1085,3149,3150],{},[1129,3151,3076],{},[1137,3153,3156],{"className":3154,"code":3155,"language":2197,"meta":1142},[2195],"Tag 10\n  seen: distance 3.0\n  or default: 3.0\n  required: 3.0\n  close: 3.0\nTag 11\n  seen: distance 3.5\n  or default: 3.5\n  required: 3.5\nTag 12\n  seen: distance 0.5\n  or default: 0.5\n  required: 0.5\n  close: 0.5\n",[1089,3157,3155],{"__ignoreMap":1142},[1085,3159,3160],{},[1129,3161,3162],{},"Scenario 5 (hidden):",[1085,3164,3165],{},[1129,3166,3065],{},[1137,3168,3171],{"className":3169,"code":3170,"language":2197,"meta":1142},[2195],"2\n7 1.25\n8 99.0\n3\n8\n7\n3\n",[1089,3172,3170],{"__ignoreMap":1142},[1085,3174,3175],{},[1129,3176,3076],{},[1137,3178,3181],{"className":3179,"code":3180,"language":2197,"meta":1142},[2195],"Tag 8\n  seen: distance 99.0\n  or default: 99.0\n  required: 99.0\nTag 7\n  seen: distance 1.25\n  or default: 1.25\n  required: 1.25\n  close: 1.25\nTag 3\n  seen: not seen\n  or default: -1.0\n  required: No tag 3\n",[1089,3182,3180],{"__ignoreMap":1142},[1085,3184,3185],{},[1129,3186,3187],{},"Scenario 6 (hidden):",[1085,3189,3190],{},[1129,3191,3065],{},[1137,3193,3196],{"className":3194,"code":3195,"language":2197,"meta":1142},[2195],"1\n1 0.0\n2\n1\n1\n",[1089,3197,3195],{"__ignoreMap":1142},[1085,3199,3200],{},[1129,3201,3076],{},[1137,3203,3206],{"className":3204,"code":3205,"language":2197,"meta":1142},[2195],"Tag 1\n  seen: distance 0.0\n  or default: 0.0\n  required: 0.0\n  close: 0.0\nTag 1\n  seen: distance 0.0\n  or default: 0.0\n  required: 0.0\n  close: 0.0\n",[1089,3207,3205],{"__ignoreMap":1142},[1085,3209,3210],{},[1129,3211,3212],{},"Solution:",[1137,3214,3216],{"className":1139,"code":3215,"language":1141,"meta":1142,"style":1142},"import java.util.HashMap;\nimport java.util.Map;\nimport java.util.Optional;\nimport java.util.Scanner;\n\npublic class Main\n{\n    public static void main(String[] args) \u002F\u002F Don't change main\n    {\n        Scanner in = new Scanner(System.in);\n        int tagCount = in.nextInt();\n        Map\u003CInteger, Double> distances = new HashMap\u003C>();\n        for (int i = 0; i \u003C tagCount; i++)\n        {\n            int id = in.nextInt();\n            distances.put(id, in.nextDouble());\n        }\n        Vision vision = new Vision(distances);\n\n        int queries = in.nextInt();\n        for (int i = 0; i \u003C queries; i++)\n        {\n            int id = in.nextInt();\n            System.out.println(\"Tag \" + id);\n            Optional\u003CDouble> distance = vision.getDistance(id);\n            System.out.println(\"  seen: \" + distance.map(d -> \"distance \" + d).orElse(\"not seen\"));\n            System.out.println(\"  or default: \" + vision.distanceOrDefault(id, -1.0));\n            try\n            {\n                System.out.println(\"  required: \" + vision.requireDistance(id));\n            }\n            catch (IllegalStateException e)\n            {\n                System.out.println(\"  required: \" + e.getMessage());\n            }\n            vision.closeDistance(id, 3.0).ifPresent(d -> System.out.println(\"  close: \" + d));\n        }\n    }\n}\n\nclass Vision\n{\n    private final Map\u003CInteger, Double> distances;\n\n    public Vision(Map\u003CInteger, Double> distances)\n    {\n        this.distances = distances;\n    }\n\n    public Optional\u003CDouble> getDistance(int id)\n    {\n        return Optional.ofNullable(distances.get(id));\n    }\n\n    public double distanceOrDefault(int id, double fallback)\n    {\n        return getDistance(id).orElse(fallback);\n    }\n\n    public double requireDistance(int id)\n    {\n        return getDistance(id).orElseThrow(() -> new IllegalStateException(\"No tag \" + id));\n    }\n\n    public Optional\u003CDouble> closeDistance(int id, double max)\n    {\n        return getDistance(id).filter(d -> d \u003C= max);\n    }\n}\n",[1089,3217,3218,3222,3226,3230,3234,3238,3242,3246,3250,3254,3258,3262,3266,3270,3274,3278,3282,3286,3290,3294,3298,3302,3306,3310,3314,3318,3322,3326,3330,3334,3338,3342,3346,3350,3354,3358,3362,3366,3370,3374,3378,3383,3388,3394,3399,3405,3410,3416,3421,3426,3432,3437,3443,3448,3453,3459,3464,3470,3475,3480,3486,3491,3497,3502,3507,3513,3518,3524,3529],{"__ignoreMap":1142},[1146,3219,3220],{"class":1148,"line":1149},[1146,3221,2862],{},[1146,3223,3224],{"class":1148,"line":1155},[1146,3225,2867],{},[1146,3227,3228],{"class":1148,"line":1161},[1146,3229,2030],{},[1146,3231,3232],{"class":1148,"line":1167},[1146,3233,2876],{},[1146,3235,3236],{"class":1148,"line":1173},[1146,3237,1221],{"emptyLinePlaceholder":1220},[1146,3239,3240],{"class":1148,"line":1179},[1146,3241,2885],{},[1146,3243,3244],{"class":1148,"line":1185},[1146,3245,1158],{},[1146,3247,3248],{"class":1148,"line":1191},[1146,3249,2894],{},[1146,3251,3252],{"class":1148,"line":1306},[1146,3253,1170],{},[1146,3255,3256],{"class":1148,"line":1312},[1146,3257,2903],{},[1146,3259,3260],{"class":1148,"line":1318},[1146,3261,2908],{},[1146,3263,3264],{"class":1148,"line":2079},[1146,3265,2913],{},[1146,3267,3268],{"class":1148,"line":2085},[1146,3269,2918],{},[1146,3271,3272],{"class":1148,"line":2090},[1146,3273,1801],{},[1146,3275,3276],{"class":1148,"line":2096},[1146,3277,2927],{},[1146,3279,3280],{"class":1148,"line":2101},[1146,3281,2932],{},[1146,3283,3284],{"class":1148,"line":2106},[1146,3285,1811],{},[1146,3287,3288],{"class":1148,"line":2112},[1146,3289,2941],{},[1146,3291,3292],{"class":1148,"line":2117},[1146,3293,1221],{"emptyLinePlaceholder":1220},[1146,3295,3296],{"class":1148,"line":2123},[1146,3297,2950],{},[1146,3299,3300],{"class":1148,"line":2129},[1146,3301,2955],{},[1146,3303,3304],{"class":1148,"line":2134},[1146,3305,1801],{},[1146,3307,3308],{"class":1148,"line":2140},[1146,3309,2927],{},[1146,3311,3312],{"class":1148,"line":2146},[1146,3313,2968],{},[1146,3315,3316],{"class":1148,"line":2151},[1146,3317,2973],{},[1146,3319,3320],{"class":1148,"line":2157},[1146,3321,2978],{},[1146,3323,3324],{"class":1148,"line":2163},[1146,3325,2983],{},[1146,3327,3328],{"class":1148,"line":2168},[1146,3329,2988],{},[1146,3331,3332],{"class":1148,"line":2174},[1146,3333,2071],{},[1146,3335,3336],{"class":1148,"line":2180},[1146,3337,2997],{},[1146,3339,3340],{"class":1148,"line":2185},[1146,3341,2082],{},[1146,3343,3344],{"class":1148,"line":3004},[1146,3345,3007],{},[1146,3347,3348],{"class":1148,"line":3010},[1146,3349,2071],{},[1146,3351,3352],{"class":1148,"line":3015},[1146,3353,3018],{},[1146,3355,3356],{"class":1148,"line":3021},[1146,3357,2082],{},[1146,3359,3360],{"class":1148,"line":3026},[1146,3361,3029],{},[1146,3363,3364],{"class":1148,"line":3032},[1146,3365,1811],{},[1146,3367,3368],{"class":1148,"line":3037},[1146,3369,1182],{},[1146,3371,3372],{"class":1148,"line":3042},[1146,3373,1194],{},[1146,3375,3376],{"class":1148,"line":3047},[1146,3377,1221],{"emptyLinePlaceholder":1220},[1146,3379,3380],{"class":1148,"line":3052},[1146,3381,3382],{},"class Vision\n",[1146,3384,3386],{"class":1148,"line":3385},42,[1146,3387,1158],{},[1146,3389,3391],{"class":1148,"line":3390},43,[1146,3392,3393],{},"    private final Map\u003CInteger, Double> distances;\n",[1146,3395,3397],{"class":1148,"line":3396},44,[1146,3398,1221],{"emptyLinePlaceholder":1220},[1146,3400,3402],{"class":1148,"line":3401},45,[1146,3403,3404],{},"    public Vision(Map\u003CInteger, Double> distances)\n",[1146,3406,3408],{"class":1148,"line":3407},46,[1146,3409,1170],{},[1146,3411,3413],{"class":1148,"line":3412},47,[1146,3414,3415],{},"        this.distances = distances;\n",[1146,3417,3419],{"class":1148,"line":3418},48,[1146,3420,1182],{},[1146,3422,3424],{"class":1148,"line":3423},49,[1146,3425,1221],{"emptyLinePlaceholder":1220},[1146,3427,3429],{"class":1148,"line":3428},50,[1146,3430,3431],{},"    public Optional\u003CDouble> getDistance(int id)\n",[1146,3433,3435],{"class":1148,"line":3434},51,[1146,3436,1170],{},[1146,3438,3440],{"class":1148,"line":3439},52,[1146,3441,3442],{},"        return Optional.ofNullable(distances.get(id));\n",[1146,3444,3446],{"class":1148,"line":3445},53,[1146,3447,1182],{},[1146,3449,3451],{"class":1148,"line":3450},54,[1146,3452,1221],{"emptyLinePlaceholder":1220},[1146,3454,3456],{"class":1148,"line":3455},55,[1146,3457,3458],{},"    public double distanceOrDefault(int id, double fallback)\n",[1146,3460,3462],{"class":1148,"line":3461},56,[1146,3463,1170],{},[1146,3465,3467],{"class":1148,"line":3466},57,[1146,3468,3469],{},"        return getDistance(id).orElse(fallback);\n",[1146,3471,3473],{"class":1148,"line":3472},58,[1146,3474,1182],{},[1146,3476,3478],{"class":1148,"line":3477},59,[1146,3479,1221],{"emptyLinePlaceholder":1220},[1146,3481,3483],{"class":1148,"line":3482},60,[1146,3484,3485],{},"    public double requireDistance(int id)\n",[1146,3487,3489],{"class":1148,"line":3488},61,[1146,3490,1170],{},[1146,3492,3494],{"class":1148,"line":3493},62,[1146,3495,3496],{},"        return getDistance(id).orElseThrow(() -> new IllegalStateException(\"No tag \" + id));\n",[1146,3498,3500],{"class":1148,"line":3499},63,[1146,3501,1182],{},[1146,3503,3505],{"class":1148,"line":3504},64,[1146,3506,1221],{"emptyLinePlaceholder":1220},[1146,3508,3510],{"class":1148,"line":3509},65,[1146,3511,3512],{},"    public Optional\u003CDouble> closeDistance(int id, double max)\n",[1146,3514,3516],{"class":1148,"line":3515},66,[1146,3517,1170],{},[1146,3519,3521],{"class":1148,"line":3520},67,[1146,3522,3523],{},"        return getDistance(id).filter(d -> d \u003C= max);\n",[1146,3525,3527],{"class":1148,"line":3526},68,[1146,3528,1182],{},[1146,3530,3532],{"class":1148,"line":3531},69,[1146,3533,1194],{},[1085,3535,3536,2402,3538,3541,3542,3544,3545,3547,3548,1948,3551,2298,3554,3556,3557,1682,3559,3561,3562,3564,3565,3567,3568,3570,3571,3574,3575,3578,3579,3582],{},[1129,3537,2401],{},[1089,3539,3540],{},"getDistance"," is the heart of it: ",[1089,3543,2762],{}," can be ",[1089,3546,1091],{},", so the right factory is ",[1089,3549,3550],{},"Optional.ofNullable",[1089,3552,3553],{},"Optional.of(map.get(id))",[1089,3555,1105],{}," the moment an unseen tag is looked up.\nThe other three methods all build on ",[1089,3558,3540],{},[1089,3560,1330],{}," for the fallback, ",[1089,3563,1334],{}," with a lambda (so the exception is only built when the value is missing), and ",[1089,3566,1461],{}," to turn a too-far\ndistance into an empty ",[1089,3569,1338],{},". A solution that uses ",[1089,3572,3573],{},"\u003C"," instead of ",[1089,3576,3577],{},"\u003C="," in the filter fails the hidden scenario with a tag exactly at the limit, and one using ",[1089,3580,3581],{},"Optional.of"," crashes on any unseen tag.",[1692,3584,1694],{},{"title":1142,"searchDepth":1155,"depth":1155,"links":3586},[3587,3588,3589],{"id":2336,"depth":1155,"text":2337},{"id":2472,"depth":1155,"text":2473},{"id":2743,"depth":1155,"text":2744},{"outlineRef":1707,"pairsWith":2323,"status":3591},"new — authored exercises (Multiple Choice + Micro-Parsons + Coding)",{"title":1012,"description":1142},"nwdkTe7Gy6gN20FQ2MPj2wFesg_vHKsQlIeHA0Kxa0o",1792718166763]