Kotlin: Uncovered - November 2017

Kotlin does a lot for us in the way of reducing boilerplate. But what is it really doing? We will be inspecting some decompiled Kotlin to discover how it does its job. By looking underneath at how it handles data classes, lambdas, and delegation, we can better understand how the language executes what we write. If you’re curious about the language, or already using it in production, you should walk away from this investigation with a deeper understanding of Kotlin, and some tools for continued exploration.

Transcript

1. Kotlin: Uncovered
   Victoria Gonda
   www.victoriagonda.com
   @TTGonda
   

   View Slide

2. collectiveidea.com @TTGonda
   Android
   Chicago
   Collective Idea
   

   View Slide

3. collectiveidea.com @TTGonda
   

   View Slide

4. collectiveidea.com @TTGonda
   “Statically typed programming language
   for modern multiplatform applications”
   

   View Slide

5. collectiveidea.com @TTGonda
   Statically Typed
   

   View Slide

6. collectiveidea.com @TTGonda
   Statically Typed
   final String name = "Victoria";
   val name = "Victoria"
   

   View Slide

7. collectiveidea.com @TTGonda
   Null Safety
   

   View Slide

8. collectiveidea.com @TTGonda
   Null Safety
   NullPointerException
   

   View Slide

9. collectiveidea.com @TTGonda
   Null Safety
   NullPointerException*
   *If you’re working with Kotlin only
   

   View Slide

10. collectiveidea.com @TTGonda
    Concise
    

    View Slide

11. collectiveidea.com @TTGonda
    map{$P=$P[$f^ord($p{$_})&6];$p{$_}=/ ^$P/ix?$P:close$_}
    Perl
    

    View Slide

12. collectiveidea.com @TTGonda
    

    View Slide

13. collectiveidea.com @TTGonda
    

    View Slide

14. collectiveidea.com @TTGonda
    Java Virtual Machine
    

    View Slide

15. collectiveidea.com @TTGonda
    Java Virtual Machine
    

    View Slide

16. collectiveidea.com @TTGonda
    Java Virtual Machine
    *.class
    

    View Slide

17. collectiveidea.com @TTGonda
    Java Virtual Machine
    *.class
    JVM dx
    

    View Slide

18. collectiveidea.com @TTGonda
    Menu > Tools > Kotlin > Show Kotlin Bytecode
    or
    CMD+SHFT+A and search “Show Kotlin Bytecode”
    

    View Slide

19. collectiveidea.com @TTGonda
    Why?
    

    View Slide

20. collectiveidea.com @TTGonda
    Data Classes
    Destructuring Class Declarations
    Companion Objects
    Null Safety
    Lambdas
    

    View Slide

21. collectiveidea.com @TTGonda
    Classes
    

    View Slide

22. collectiveidea.com @TTGonda
    class Cupcake(
    val flavor: String,
    var icing: String?
    )
    Classes
    

    View Slide

23. collectiveidea.com @TTGonda
    package com.victoriagonda.v2;
    import kotlin.Metadata;
    import kotlin.jvm.internal.Intrinsics;
    import org.jetbrains.annotations.NotNull;
    import org.jetbrains.annotations.Nullable;
    @Metadata(
    mv = {1, 1, 7},
    bv = {1, 0, 2},
    k = 1,
    d1 =
    {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\b\u0018\u00002\u00020\u0001B\u0017\u0012\
    u0006\u0010\u0002\u001a\u00020\u0003\u0012\b\u0010\u0004\u001a\u0004\u0018\u00010\u0003¢
    \u0006\u0002\u0010\u0005R\u0011\u0010\u0002\u001a\u00020\u0003¢
    \u0006\b\n\u0000\u001a\u0004\b\u0006\u0010\u0007R\u001c\u0010\u0004\u001a\u0004\u0018\u00010\u0003X\u0086\u000e¢
    \u0006\u000e\n\u0000\u001a\u0004\b\b\u0010\u0007\"\u0004\b\t\u0010\n¨\u0006\u000b"},
    d2 = {"Lcom/victoriagonda/v2/Cupcake;", "", "flavor", "", "icing", "(Ljava/lang/String;Ljava/lang/String;)V", "getFlavor",
    "()Ljava/lang/String;", "getIcing", "setIcing", "(Ljava/lang/String;)V", "production sources for module app"}
    )
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    super();
    this.flavor = flavor;
    this.icing = icing;
    

    View Slide

24. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    super();
    this.flavor = flavor;
    this.icing = icing;
    }
    }
    

    View Slide

25. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    

    View Slide

26. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    

    View Slide

27. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    

    View Slide

28. collectiveidea.com @TTGonda
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    super();
    this.flavor = flavor;
    this.icing = icing;
    }
    }
    

    View Slide

29. collectiveidea.com @TTGonda
    Null Safety Benchmark
    

    View Slide

30. collectiveidea.com @TTGonda
    data class Cupcake(
    val flavor: String,
    var icing: String?
    )
    Data Classes
    

    View Slide

31. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    super();
    this.flavor = flavor;
    this.icing = icing;
    }
    @NotNull
    public final String component1() {
    return this.flavor;
    }
    @Nullable
    public final String component2() {
    return this.icing;
    }
    @NotNull
    public final Cupcake copy(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    return new Cupcake(flavor, icing);
    }
    // $FF: synthetic method
    // $FF: bridge method
    @NotNull
    public static Cupcake copy$default(Cupcake var0, String var1, String var2, int var3, Object var4) {
    if((var3 & 1) != 0) {
    var1 = var0.flavor;
    }
    if((var3 & 2) != 0) {
    var2 = var0.icing;
    }
    return var0.copy(var1, var2);
    }
    public String toString() {
    return "Cupcake(flavor=" + this.flavor + ", icing=" + this.icing + ")";
    }
    public int hashCode() {
    return (this.flavor != null?this.flavor.hashCode():0) * 31 + (this.icing != null?this.icing.hashCode():0);
    }
    public boolean equals(Object var1) {
    if(this != var1) {
    if(var1 instanceof Cupcake) {
    Cupcake var2 = (Cupcake)var1;
    if(Intrinsics.areEqual(this.flavor, var2.flavor) && Intrinsics.areEqual(this.icing, var2.icing)) {
    return true;
    }
    }
    return false;
    } else {
    return true;
    }
    }
    }
    

    View Slide

32. collectiveidea.com @TTGonda
    @NotNull
    public final String component1() {
    return this.flavor;
    }
    @Nullable
    public final String component2() {
    return this.icing;
    }
    @NotNull
    public final Cupcake copy(
    @NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    return new Cupcake(flavor, icing);
    }
    // $FF: synthetic method
    // $FF: bridge method
    @NotNull
    public static Cupcake copy$default(
    Cupcake var0, String var1, String var2, int var3, Object var4) {
    if((var3 & 1) != 0) {
    var1 = var0.flavor;
    }
    

    View Slide

33. collectiveidea.com @TTGonda
    @NotNull
    public final Cupcake copy(
    @NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    return new Cupcake(flavor, icing);
    }
    // $FF: synthetic method
    // $FF: bridge method
    @NotNull
    public static Cupcake copy$default(
    Cupcake var0, String var1, String var2, int var3, Object var4) {
    if((var3 & 1) != 0) {
    var1 = var0.flavor;
    }
    if((var3 & 2) != 0) {
    var2 = var0.icing;
    }
    return var0.copy(var1, var2);
    }
    public String toString() {
    return "Cupcake(flavor=" +
    

    View Slide

34. collectiveidea.com @TTGonda
    val cupcake = Cupcake("Chocolate", "Peanut Butter”)

    val copy = cupcake.copy()

    val noIcing = cupcake.copy(icing = null)

    val vanilla = cupcake.copy(flavor = “Vanilla")

    val banana = cupcake.copy(

    flavor = "Banana", 

    icing = "Chocolate")
    

    View Slide

35. collectiveidea.com @TTGonda
    @NotNull
    public static Cupcake copy$default(
    Cupcake var0, String var1, String var2, int var3, Object var4) {
    if((var3 & 1) != 0) {
    var1 = var0.flavor;
    }
    if((var3 & 2) != 0) {
    var2 = var0.icing;
    }
    return var0.copy(var1, var2);
    }
    public String toString() {
    return "Cupcake(flavor=" +
    this.flavor +
    ", icing=" +
    this.icing +
    ")";
    }
    public int hashCode() {
    return (this.flavor != null?this.flavor.hashCode():0) * 31 +
    (this.icing != null?this.icing.hashCode():0);
    }
    

    View Slide

36. collectiveidea.com @TTGonda
    ")";
    }
    public int hashCode() {
    return (this.flavor != null?this.flavor.hashCode():0) * 31 +
    (this.icing != null?this.icing.hashCode():0);
    }
    public boolean equals(Object var1) {
    if(this != var1) {
    if(var1 instanceof Cupcake) {
    Cupcake var2 = (Cupcake)var1;
    if(Intrinsics.areEqual(this.flavor, var2.flavor) &&
    Intrinsics.areEqual(this.icing, var2.icing)) {
    return true;
    }
    }
    return false;
    } else {
    return true;
    }
    }
    }
    

    View Slide

37. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private final String flavor;
    @Nullable
    private String icing;
    @NotNull
    public final String getFlavor() {
    return this.flavor;
    }
    @Nullable
    public final String getIcing() {
    return this.icing;
    }
    public final void setIcing(@Nullable String var1) {
    this.icing = var1;
    }
    public Cupcake(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    super();
    this.flavor = flavor;
    this.icing = icing;
    }
    @NotNull
    public final String component1() {
    return this.flavor;
    }
    @Nullable
    public final String component2() {
    return this.icing;
    }
    @NotNull
    public final Cupcake copy(@NotNull String flavor, @Nullable String icing) {
    Intrinsics.checkParameterIsNotNull(flavor, "flavor");
    return new Cupcake(flavor, icing);
    }
    // $FF: synthetic method
    // $FF: bridge method
    @NotNull
    public static Cupcake copy$default(Cupcake var0, String var1, String var2, int var3, Object var4) {
    if((var3 & 1) != 0) {
    var1 = var0.flavor;
    }
    if((var3 & 2) != 0) {
    var2 = var0.icing;
    }
    return var0.copy(var1, var2);
    }
    public String toString() {
    return "Cupcake(flavor=" + this.flavor + ", icing=" + this.icing + ")";
    }
    public int hashCode() {
    return (this.flavor != null?this.flavor.hashCode():0) * 31 + (this.icing != null?this.icing.hashCode():0);
    }
    public boolean equals(Object var1) {
    if(this != var1) {
    if(var1 instanceof Cupcake) {
    Cupcake var2 = (Cupcake)var1;
    if(Intrinsics.areEqual(this.flavor, var2.flavor) && Intrinsics.areEqual(this.icing, var2.icing)) {
    return true;
    }
    }
    return false;
    } else {
    return true;
    }
    }
    }
    

    View Slide

38. collectiveidea.com @TTGonda
    Destructuring Class
    Declarations
    

    View Slide

39. collectiveidea.com @TTGonda
    Reminder
    @NotNull
    public final String component1() {
    return this.flavor;
    }
    @Nullable
    public final String component2() {
    return this.icing;
    }
    

    View Slide

40. collectiveidea.com @TTGonda
    val cupcake = Cupcake("Vanilla", “Chocolate")
    val (flavor, icing) = cupcake
    return "$flavor cake with $icing icing”
    // Vanilla cake with Chocolate icing
    

    View Slide

41. collectiveidea.com @TTGonda
    Cupcake cupcake = new Cupcake("Vanilla", “Chocolate");
    String flavor = cupcake.component1();
    String icing = cupcake.component2();
    return "" + flavor + "cake with" + icing + “icing";
    // Vanilla cake with Chocolate icing
    

    View Slide

42. collectiveidea.com @TTGonda
    cupcakes.forEach { (flavor, icing) ->
    println("$flavor $icing")
    }
    

    View Slide

43. collectiveidea.com @TTGonda
    Iterable $receiver$iv = (Iterable)cupcakes;
    Iterator var2 = $receiver$iv.iterator();
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    Cupcake $flavor_icing = (Cupcake)element$iv;
    String flavor = $flavor_icing.component1();
    String icing = $flavor_icing.component2();
    String var7 = "" + flavor + ' ' + icing;
    System.out.println(var7);
    }
    

    View Slide

44. collectiveidea.com @TTGonda
    Iterable $receiver$iv = (Iterable)cupcakes;
    Iterator var2 = $receiver$iv.iterator();
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    Cupcake $flavor_icing = (Cupcake)element$iv;
    String flavor = $flavor_icing.component1();
    String icing = $flavor_icing.component2();
    String var7 = "" + flavor + ' ' + icing;
    System.out.println(var7);
    }
    

    View Slide

45. collectiveidea.com @TTGonda
    Companion Objects
    

    View Slide

46. collectiveidea.com @TTGonda
    class Cupcake() {
    companion object {
    val FLAVOR_VANILLA = "Vanilla"
    val FLAVOR_CHOCOLATE = "Chocolate"
    }
    }
    

    View Slide

47. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private static final String FLAVOR_VANILLA = "Vanilla";
    @NotNull
    private static final String FLAVOR_CHOCOLATE = "Chocolate";
    public static final Cupcake.Companion Companion =
    new Cupcake.Companion((DefaultConstructorMarker)null);
    public static final class Companion {
    @NotNull
    public final String getFLAVOR_VANILLA() {
    return Cupcake.FLAVOR_VANILLA;
    }
    @NotNull
    public final String getFLAVOR_CHOCOLATE() {
    return Cupcake.FLAVOR_CHOCOLATE;
    }
    private Companion() {
    }
    }
    }
    

    View Slide

48. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private static final String FLAVOR_VANILLA = "Vanilla";
    @NotNull
    private static final String FLAVOR_CHOCOLATE = "Chocolate";
    public static final Cupcake.Companion Companion =
    new Cupcake.Companion((DefaultConstructorMarker)null);
    public static final class Companion {
    @NotNull
    public final String getFLAVOR_VANILLA() {
    return Cupcake.FLAVOR_VANILLA;
    }
    @NotNull
    public final String getFLAVOR_CHOCOLATE() {
    return Cupcake.FLAVOR_CHOCOLATE;
    }
    private Companion() {
    }
    }
    }
    

    View Slide

49. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    private static final String FLAVOR_VANILLA = "Vanilla";
    @NotNull
    private static final String FLAVOR_CHOCOLATE = "Chocolate";
    public static final Cupcake.Companion Companion =
    new Cupcake.Companion((DefaultConstructorMarker)null);
    public static final class Companion {
    @NotNull
    public final String getFLAVOR_VANILLA() {
    return Cupcake.FLAVOR_VANILLA;
    }
    @NotNull
    public final String getFLAVOR_CHOCOLATE() {
    return Cupcake.FLAVOR_CHOCOLATE;
    }
    private Companion() {
    }
    }
    }
    

    View Slide

50. collectiveidea.com @TTGonda
    class Cupcake() {
    companion object {
    const val FLAVOR_VANILLA = "Vanilla"
    const val FLAVOR_CHOCOLATE = "Chocolate"
    }
    }
    

    View Slide

51. collectiveidea.com @TTGonda
    public final class Cupcake {
    @NotNull
    public static final String FLAVOR_VANILLA = "Vanilla";
    @NotNull
    public static final String FLAVOR_CHOCOLATE = "Chocolate";
    public static final Cupcake.Companion Companion =
    new Cupcake.Companion((DefaultConstructorMarker)null);
    public static final class Companion {
    private Companion() {
    }
    }
    }
    

    View Slide

52. collectiveidea.com @TTGonda
    Null Safety
    

    View Slide

53. collectiveidea.com @TTGonda
    val icecream: IceCream?
    

    View Slide

54. collectiveidea.com @TTGonda
    icecream.flavor
    

    View Slide

55. collectiveidea.com @TTGonda
    if (icecream != null) {
    return icecream.flavor
    } else {
    return null
    }
    

    View Slide

56. collectiveidea.com @TTGonda
    return icecream?.flavor
    Safe Call Operator
    

    View Slide

57. collectiveidea.com @TTGonda
    return icecream != null?icecream.getFlavor():null;
    Safe Call Operator
    

    View Slide

58. collectiveidea.com @TTGonda
    return icecream!!.flavor
    !! Operator
    

    View Slide

59. collectiveidea.com @TTGonda
    IceCream var10000 = icecream;
    if(icecream == null) {
    Intrinsics.throwNpe();
    }
    return var10000.getFlavor();
    !! Operator
    

    View Slide

60. collectiveidea.com @TTGonda
    return icecream?.flavor ?: "Chocolate Chip"
    Elvis Operator
    

    View Slide

61. collectiveidea.com @TTGonda
    IceCream var10000 = icecream;
    String var0;
    if(icecream != null) {
    var0 = var10000.getFlavor();
    if(var0 != null) {
    return var0;
    }
    }
    var0 = "Chocolate Chip";
    return var0;
    Elvis Operator
    

    View Slide

62. collectiveidea.com @TTGonda
    return icecream?.let({ nonNullIceCream ->

    nonNullIceCream.flavor })

    return icecream?.let({ it.flavor })

    return icecream?.let { it.flavor }

    return icecream?.let(IceCream::flavor)
    Null Safe Scoping
    

    View Slide

63. collectiveidea.com @TTGonda
    IceCream var10000 = icecream;
    String var3;
    if(icecream != null) {
    IceCream var0 = var10000;
    var3 = var0.getFlavor();
    } else {
    var3 = null;
    }
    return var3;
    Null Safe Scoping
    

    View Slide

64. collectiveidea.com @TTGonda
    Lambdas
    

    View Slide

65. collectiveidea.com @TTGonda
    inline fun makePie(prepareFilling: () -> Filling) {
    makeCrust()
    val filling = prepareFilling()
    addFilling(filling)
    bakePie()
    }
    

    View Slide

66. collectiveidea.com @TTGonda
    public static final void makePie(
    @NotNull Function0 prepareFilling) {
    Intrinsics.checkParameterIsNotNull(
    prepareFilling, “prepareFilling”);
    makeCrust();
    Filling filling = (Filling)prepareFilling.invoke();
    addFilling(filling);
    bakePie();
    }
    

    View Slide

67. collectiveidea.com @TTGonda
    fun makeApplePie() {
    makePie {
    Apples()
    .cut()
    .addSpices()
    .toFilling()
    }
    }
    

    View Slide

68. collectiveidea.com @TTGonda
    public static final void makeApplePie() {
    makeCrust();
    Filling filling$iv =
    (new Apples()).cut().addSpices().toFilling();
    addFilling(filling$iv);
    bakePie();
    }
    

    View Slide

69. collectiveidea.com @TTGonda
    fun makePie(prepareFilling: () -> Filling) {
    makeCrust()
    val filling = prepareFilling()
    addFilling(filling)
    bakePie()
    }
    

    View Slide

70. collectiveidea.com @TTGonda
    public static final void makeApplePie() {
    makePie((Function0)null.INSTANCE);
    }
    

    View Slide

71. collectiveidea.com @TTGonda
    LINENUMBER 43 L6
    NEW com/victoriagonda/v2/Apples
    DUP
    INVOKESPECIAL com/victoriagonda/v2/Apples. ()V
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    L9
    LINENUMBER 46 L9
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.toFilling ()Lcom/victoriagonda/v2/Filling;
    L10
    ARETURN
    L11
    LOCALVARIABLE this Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; L0 L11 0
    MAXSTACK = 2
    MAXLOCALS = 1
    // access flags 0x19
    public final static Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; INSTANCE
    // access flags 0x8
    static ()V
    NEW com/victoriagonda/v2/LambdasKt$makeApplePie$1
    DUP
    INVOKESPECIAL com/victoriagonda/v2/LambdasKt$makeApplePie$1. ()V
    PUTSTATIC com/victoriagonda/v2/LambdasKt$makeApplePie$1.INSTANCE :
    Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1;
    RETURN
    MAXSTACK = 2
    MAXLOCALS = 0
    

    View Slide

72. collectiveidea.com @TTGonda
    final class com/victoriagonda/v2/LambdasKt$makeApplePie$1
    extends kotlin/jvm/internal/Lambda
    implements kotlin/jvm/functions/Function0 {
    // access flags 0x11
    public final invoke()Lcom/victoriagonda/v2/Filling;
    @Lorg/jetbrains/annotations/NotNull;() // invisible
    L0
    LINENUMBER 43 L0
    L1
    LINENUMBER 46 L1
    L2
    LINENUMBER 43 L2
    L3
    LINENUMBER 45 L3
    L4
    LINENUMBER 43 L4
    L5
    LINENUMBER 44 L5
    L6
    LINENUMBER 43 L6
    NEW com/victoriagonda/v2/Apples
    DUP
    INVOKESPECIAL com/victoriagonda/v2/Apples. ()V
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    

    View Slide

73. collectiveidea.com @TTGonda
    final class com/victoriagonda/v2/LambdasKt$makeApplePie$1
    extends kotlin/jvm/internal/Lambda
    implements kotlin/jvm/functions/Function0 {
    // access flags 0x11
    public final invoke()Lcom/victoriagonda/v2/Filling;
    @Lorg/jetbrains/annotations/NotNull;() // invisible
    L0
    LINENUMBER 43 L0
    L1
    LINENUMBER 46 L1
    L2
    LINENUMBER 43 L2
    L3
    LINENUMBER 45 L3
    L4
    LINENUMBER 43 L4
    L5
    LINENUMBER 44 L5
    L6
    LINENUMBER 43 L6
    NEW com/victoriagonda/v2/Apples
    DUP
    INVOKESPECIAL com/victoriagonda/v2/Apples. ()V
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    

    View Slide

74. collectiveidea.com @TTGonda
    final class com/victoriagonda/v2/LambdasKt$makeApplePie$1
    extends kotlin/jvm/internal/Lambda
    implements kotlin/jvm/functions/Function0 {
    // access flags 0x11
    public final invoke()Lcom/victoriagonda/v2/Filling;
    @Lorg/jetbrains/annotations/NotNull;() // invisible
    L0
    LINENUMBER 43 L0
    L1
    LINENUMBER 46 L1
    L2
    LINENUMBER 43 L2
    L3
    LINENUMBER 45 L3
    L4
    LINENUMBER 43 L4
    L5
    LINENUMBER 44 L5
    L6
    LINENUMBER 43 L6
    NEW com/victoriagonda/v2/Apples
    DUP
    INVOKESPECIAL com/victoriagonda/v2/Apples. ()V
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    

    View Slide

75. collectiveidea.com @TTGonda
    L2
    LINENUMBER 43 L2
    L3
    LINENUMBER 45 L3
    L4
    LINENUMBER 43 L4
    L5
    LINENUMBER 44 L5
    L6
    LINENUMBER 43 L6
    NEW com/victoriagonda/v2/Apples
    DUP
    INVOKESPECIAL com/victoriagonda/v2/Apples. ()V
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    L9
    LINENUMBER 46 L9
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.toFilling ()Lcom/victoriagonda/v2/Filling;
    L10
    ARETURN
    L11
    LOCALVARIABLE this Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; L0 L11 0
    MAXSTACK = 2
    MAXLOCALS = 1
    // access flags 0x19
    public final static Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; INSTANCE
    

    View Slide

76. collectiveidea.com @TTGonda
    L7
    LINENUMBER 44 L7
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.cut ()Lcom/victoriagonda/v2/Apples;
    L8
    LINENUMBER 45 L8
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.addSpices ()Lcom/victoriagonda/v2/Apples;
    L9
    LINENUMBER 46 L9
    INVOKEVIRTUAL com/victoriagonda/v2/Apples.toFilling ()Lcom/victoriagonda/v2/Filling;
    L10
    ARETURN
    L11
    LOCALVARIABLE this Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; L0 L11 0
    MAXSTACK = 2
    MAXLOCALS = 1
    // access flags 0x19
    public final static Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1; INSTANCE
    // access flags 0x8
    static ()V
    NEW com/victoriagonda/v2/LambdasKt$makeApplePie$1
    DUP
    INVOKESPECIAL com/victoriagonda/v2/LambdasKt$makeApplePie$1. ()V
    PUTSTATIC com/victoriagonda/v2/LambdasKt$makeApplePie$1.INSTANCE :
    Lcom/victoriagonda/v2/LambdasKt$makeApplePie$1;
    RETURN
    MAXSTACK = 2
    MAXLOCALS = 0
    

    View Slide

77. collectiveidea.com @TTGonda
    public static final void makeApplePie() {
    makePie((Function0)null.INSTANCE);
    }
    

    View Slide

78. collectiveidea.com @TTGonda
    Smart Casting
    Collection Functions
    Control Flow Structures
    Operator Overloading
    Named Parameters
    Extension Functions
    Delegation
    

    View Slide

79. collectiveidea.com @TTGonda
    Code > Convert Java File to Kotlin File
    or
    CMD+SHFT+A and search “Convert Java File to Kotlin File”
    

    View Slide

80. Thanks!
    Victoria Gonda
    www.victoriagonda.com
    @TTGonda
    

    View Slide

81. collectiveidea.com @TTGonda
    

    View Slide