http://fastutil.di.unimi.it/: fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists and priority queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
  • Sebastiano Vigna 
public class it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction<V> implements it.unimi.dsi.fastutil.doubles.Double2ReferenceFunction<V>
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction
  super_class: java.lang.Object
{
  protected final java.util.function.Function<? super java.lang.Double, ? extends V> function;
    descriptor: Ljava/util/function/Function;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL
    Signature: Ljava/util/function/Function<-Ljava/lang/Double;+TV;>;

  protected void <init>(java.util.function.Function<? super java.lang.Double, ? extends V>);
    descriptor: (Ljava/util/function/Function;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // java.util.function.Function function
         0: .line 452
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 453
            aload 0 /* this */
            aload 1 /* function */
            putfield it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.function:Ljava/util/function/Function;
         2: .line 454
            return
        end local 1 // java.util.function.Function function
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    3     0      this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    3     1  function  Ljava/util/function/Function<-Ljava/lang/Double;+TV;>;
    Signature: (Ljava/util/function/Function<-Ljava/lang/Double;+TV;>;)V
    MethodParameters:
          Name  Flags
      function  

  public boolean containsKey(double);
    descriptor: (D)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // double key
         0: .line 457
            aload 0 /* this */
            getfield it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.function:Ljava/util/function/Function;
            dload 1 /* key */
            invokestatic java.lang.Double.valueOf:(D)Ljava/lang/Double;
            invokeinterface java.util.function.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            ifnull 1
            iconst_1
            ireturn
      StackMap locals:
      StackMap stack:
         1: iconst_0
            ireturn
        end local 1 // double key
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    2     1   key  D
    MethodParameters:
      Name  Flags
      key   

  public boolean containsKey(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // java.lang.Object key
         0: .line 463
            aload 1 /* key */
            ifnonnull 2
         1: .line 464
            iconst_0
            ireturn
         2: .line 465
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.function:Ljava/util/function/Function;
            aload 1 /* key */
            checkcast java.lang.Double
            invokeinterface java.util.function.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            ifnull 3
            iconst_1
            ireturn
      StackMap locals:
      StackMap stack:
         3: iconst_0
            ireturn
        end local 1 // java.lang.Object key
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    4     1   key  Ljava/lang/Object;
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()
    MethodParameters:
      Name  Flags
      key   

  public V get();
    descriptor: (D)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=4, args_size=2
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // double key
         0: .line 470
            aload 0 /* this */
            getfield it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.function:Ljava/util/function/Function;
            dload 1 /* key */
            invokestatic java.lang.Double.valueOf:(D)Ljava/lang/Double;
            invokeinterface java.util.function.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            astore 3 /* v */
        start local 3 // java.lang.Object v
         1: .line 471
            aload 3 /* v */
            ifnonnull 3
         2: .line 472
            aconst_null
            areturn
         3: .line 473
      StackMap locals: java.lang.Object
      StackMap stack:
            aload 3 /* v */
            areturn
        end local 3 // java.lang.Object v
        end local 1 // double key
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    4     1   key  D
            1    4     3     v  TV;
    Signature: (D)TV;
    MethodParameters:
      Name  Flags
      key   

  public V get();
    descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // java.lang.Object key
         0: .line 479
            aload 1 /* key */
            ifnonnull 2
         1: .line 480
            aconst_null
            areturn
         2: .line 481
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.function:Ljava/util/function/Function;
            aload 1 /* key */
            checkcast java.lang.Double
            invokeinterface java.util.function.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            areturn
        end local 1 // java.lang.Object key
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    3     1   key  Ljava/lang/Object;
    Signature: (Ljava/lang/Object;)TV;
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()
    MethodParameters:
      Name  Flags
      key   

  public V put(java.lang.Double, );
    descriptor: (Ljava/lang/Double;Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
        start local 1 // java.lang.Double key
        start local 2 // java.lang.Object value
         0: .line 486
            new java.lang.UnsupportedOperationException
            dup
            invokespecial java.lang.UnsupportedOperationException.<init>:()V
            athrow
        end local 2 // java.lang.Object value
        end local 1 // java.lang.Double key
        end local 0 // it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    1     0   this  Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunctions$PrimitiveFunction<TV;>;
            0    1     1    key  Ljava/lang/Double;
            0    1     2  value  TV;
    Signature: (Ljava/lang/Double;TV;)TV;
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()
    MethodParameters:
       Name  Flags
      key    final
      value  final

  public java.lang.Object put(java.lang.Object, java.lang.Object);
    descriptor: (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x1041) ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=3, locals=3, args_size=3
         0: .line 1
            aload 0
            aload 1
            checkcast java.lang.Double
            aload 2
            checkcast java.lang.Object
            invokevirtual it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction.put:(Ljava/lang/Double;Ljava/lang/Object;)Ljava/lang/Object;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: <V:Ljava/lang/Object;>Ljava/lang/Object;Lit/unimi/dsi/fastutil/doubles/Double2ReferenceFunction<TV;>;
SourceFile: "Double2ReferenceFunctions.java"
NestHost: it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions
InnerClasses:
  public PrimitiveFunction = it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions$PrimitiveFunction of it.unimi.dsi.fastutil.doubles.Double2ReferenceFunctions