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 final class it.unimi.dsi.fastutil.objects.ReferenceSets
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: it.unimi.dsi.fastutil.objects.ReferenceSets
  super_class: java.lang.Object
{
  public static final it.unimi.dsi.fastutil.objects.ReferenceSets$EmptySet EMPTY_SET;
    descriptor: Lit/unimi/dsi/fastutil/objects/ReferenceSets$EmptySet;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 65
            new it.unimi.dsi.fastutil.objects.ReferenceSets$EmptySet
            dup
            invokespecial it.unimi.dsi.fastutil.objects.ReferenceSets$EmptySet.<init>:()V
            putstatic it.unimi.dsi.fastutil.objects.ReferenceSets.EMPTY_SET:Lit/unimi/dsi/fastutil/objects/ReferenceSets$EmptySet;
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // it.unimi.dsi.fastutil.objects.ReferenceSets this
         0: .line 26
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 27
            return
        end local 0 // it.unimi.dsi.fastutil.objects.ReferenceSets this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lit/unimi/dsi/fastutil/objects/ReferenceSets;

  public static <K> it.unimi.dsi.fastutil.objects.ReferenceSet<K> emptySet();
    descriptor: ()Lit/unimi/dsi/fastutil/objects/ReferenceSet;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: .line 76
            getstatic it.unimi.dsi.fastutil.objects.ReferenceSets.EMPTY_SET:Lit/unimi/dsi/fastutil/objects/ReferenceSets$EmptySet;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
    Signature: <K:Ljava/lang/Object;>()Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;

  public static <K> it.unimi.dsi.fastutil.objects.ReferenceSet<K> singleton(K);
    descriptor: (Ljava/lang/Object;)Lit/unimi/dsi/fastutil/objects/ReferenceSet;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // java.lang.Object element
         0: .line 133
            new it.unimi.dsi.fastutil.objects.ReferenceSets$Singleton
            dup
            aload 0 /* element */
            invokespecial it.unimi.dsi.fastutil.objects.ReferenceSets$Singleton.<init>:(Ljava/lang/Object;)V
            areturn
        end local 0 // java.lang.Object element
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    1     0  element  TK;
    Signature: <K:Ljava/lang/Object;>(TK;)Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    MethodParameters:
         Name  Flags
      element  final

  public static <K> it.unimi.dsi.fastutil.objects.ReferenceSet<K> synchronize(it.unimi.dsi.fastutil.objects.ReferenceSet<K>);
    descriptor: (Lit/unimi/dsi/fastutil/objects/ReferenceSet;)Lit/unimi/dsi/fastutil/objects/ReferenceSet;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
         0: .line 164
            new it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet
            dup
            aload 0 /* s */
            invokespecial it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet.<init>:(Lit/unimi/dsi/fastutil/objects/ReferenceSet;)V
            areturn
        end local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0     s  Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    Signature: <K:Ljava/lang/Object;>(Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;)Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    MethodParameters:
      Name  Flags
      s     final

  public static <K> it.unimi.dsi.fastutil.objects.ReferenceSet<K> synchronize(it.unimi.dsi.fastutil.objects.ReferenceSet<K>, );
    descriptor: (Lit/unimi/dsi/fastutil/objects/ReferenceSet;Ljava/lang/Object;)Lit/unimi/dsi/fastutil/objects/ReferenceSet;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=4, locals=2, args_size=2
        start local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
        start local 1 // java.lang.Object sync
         0: .line 178
            new it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet
            dup
            aload 0 /* s */
            aload 1 /* sync */
            invokespecial it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet.<init>:(Lit/unimi/dsi/fastutil/objects/ReferenceSet;Ljava/lang/Object;)V
            areturn
        end local 1 // java.lang.Object sync
        end local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0     s  Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
            0    1     1  sync  Ljava/lang/Object;
    Signature: <K:Ljava/lang/Object;>(Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;Ljava/lang/Object;)Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    MethodParameters:
      Name  Flags
      s     final
      sync  final

  public static <K> it.unimi.dsi.fastutil.objects.ReferenceSet<K> unmodifiable(it.unimi.dsi.fastutil.objects.ReferenceSet<K>);
    descriptor: (Lit/unimi/dsi/fastutil/objects/ReferenceSet;)Lit/unimi/dsi/fastutil/objects/ReferenceSet;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
         0: .line 214
            new it.unimi.dsi.fastutil.objects.ReferenceSets$UnmodifiableSet
            dup
            aload 0 /* s */
            invokespecial it.unimi.dsi.fastutil.objects.ReferenceSets$UnmodifiableSet.<init>:(Lit/unimi/dsi/fastutil/objects/ReferenceSet;)V
            areturn
        end local 0 // it.unimi.dsi.fastutil.objects.ReferenceSet s
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0     s  Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    Signature: <K:Ljava/lang/Object;>(Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;)Lit/unimi/dsi/fastutil/objects/ReferenceSet<TK;>;
    MethodParameters:
      Name  Flags
      s     final
}
SourceFile: "ReferenceSets.java"
NestMembers:
  it.unimi.dsi.fastutil.objects.ReferenceSets$EmptySet  it.unimi.dsi.fastutil.objects.ReferenceSets$Singleton  it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet  it.unimi.dsi.fastutil.objects.ReferenceSets$UnmodifiableSet
InnerClasses:
  public EmptySet = it.unimi.dsi.fastutil.objects.ReferenceSets$EmptySet of it.unimi.dsi.fastutil.objects.ReferenceSets
  public Singleton = it.unimi.dsi.fastutil.objects.ReferenceSets$Singleton of it.unimi.dsi.fastutil.objects.ReferenceSets
  public SynchronizedSet = it.unimi.dsi.fastutil.objects.ReferenceSets$SynchronizedSet of it.unimi.dsi.fastutil.objects.ReferenceSets
  public UnmodifiableSet = it.unimi.dsi.fastutil.objects.ReferenceSets$UnmodifiableSet of it.unimi.dsi.fastutil.objects.ReferenceSets