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 abstract class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction<K, V> implements it.unimi.dsi.fastutil.objects.Object2ObjectFunction<K, V>, java.io.Serializable
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction
  super_class: java.lang.Object
{
  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: -4940583368468432370

  protected V defRetValue;
    descriptor: Ljava/lang/Object;
    flags: (0x0004) ACC_PROTECTED
    Signature: TV;

  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
         0: .line 34
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 35
            return
        end local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lit/unimi/dsi/fastutil/objects/AbstractObject2ObjectFunction<TK;TV;>;

  public void defaultReturnValue();
    descriptor: (Ljava/lang/Object;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
        start local 1 // java.lang.Object rv
         0: .line 43
            aload 0 /* this */
            aload 1 /* rv */
            putfield it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction.defRetValue:Ljava/lang/Object;
         1: .line 44
            return
        end local 1 // java.lang.Object rv
        end local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lit/unimi/dsi/fastutil/objects/AbstractObject2ObjectFunction<TK;TV;>;
            0    2     1    rv  TV;
    Signature: (TV;)V
    MethodParameters:
      Name  Flags
      rv    final

  public V defaultReturnValue();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
         0: .line 47
            aload 0 /* this */
            getfield it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction.defRetValue:Ljava/lang/Object;
            areturn
        end local 0 // it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lit/unimi/dsi/fastutil/objects/AbstractObject2ObjectFunction<TK;TV;>;
    Signature: ()TV;
}
Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>Ljava/lang/Object;Lit/unimi/dsi/fastutil/objects/Object2ObjectFunction<TK;TV;>;Ljava/io/Serializable;
SourceFile: "AbstractObject2ObjectFunction.java"