https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
class com.google.common.collect.AbstractBiMap$ValueSet extends com.google.common.collect.ForwardingSet<V>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.AbstractBiMap$ValueSet
  super_class: com.google.common.collect.ForwardingSet
{
  final java.util.Set<V> valuesDelegate;
    descriptor: Ljava/util/Set;
    flags: (0x0010) ACC_FINAL
    Signature: Ljava/util/Set<TV;>;

  final com.google.common.collect.AbstractBiMap this$0;
    descriptor: Lcom/google/common/collect/AbstractBiMap;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  private void <init>(com.google.common.collect.AbstractBiMap);
    descriptor: (Lcom/google/common/collect/AbstractBiMap;)V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
         0: .line 272
            aload 0 /* this */
            aload 1
            putfield com.google.common.collect.AbstractBiMap$ValueSet.this$0:Lcom/google/common/collect/AbstractBiMap;
            aload 0 /* this */
            invokespecial com.google.common.collect.ForwardingSet.<init>:()V
         1: .line 273
            aload 0 /* this */
            aload 1
            getfield com.google.common.collect.AbstractBiMap.inverse:Lcom/google/common/collect/AbstractBiMap;
            invokevirtual com.google.common.collect.AbstractBiMap.keySet:()Ljava/util/Set;
            putfield com.google.common.collect.AbstractBiMap$ValueSet.valuesDelegate:Ljava/util/Set;
         2: .line 272
            return
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/google/common/collect/AbstractBiMap$ValueSet;
    MethodParameters:
        Name  Flags
      this$0  final

  protected java.util.Set<V> delegate();
    descriptor: ()Ljava/util/Set;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
         0: .line 277
            aload 0 /* this */
            getfield com.google.common.collect.AbstractBiMap$ValueSet.valuesDelegate:Ljava/util/Set;
            areturn
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/AbstractBiMap$ValueSet;
    Signature: ()Ljava/util/Set<TV;>;

  public java.util.Iterator<V> iterator();
    descriptor: ()Ljava/util/Iterator;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
         0: .line 282
            aload 0 /* this */
            getfield com.google.common.collect.AbstractBiMap$ValueSet.this$0:Lcom/google/common/collect/AbstractBiMap;
            invokevirtual com.google.common.collect.AbstractBiMap.entrySet:()Ljava/util/Set;
            invokeinterface java.util.Set.iterator:()Ljava/util/Iterator;
            invokestatic com.google.common.collect.Maps.valueIterator:(Ljava/util/Iterator;)Ljava/util/Iterator;
            areturn
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/AbstractBiMap$ValueSet;
    Signature: ()Ljava/util/Iterator<TV;>;

  public java.lang.Object[] toArray();
    descriptor: ()[Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
         0: .line 287
            aload 0 /* this */
            invokevirtual com.google.common.collect.AbstractBiMap$ValueSet.standardToArray:()[Ljava/lang/Object;
            areturn
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/AbstractBiMap$ValueSet;

  public <T> T[] toArray();
    descriptor: ([Ljava/lang/Object;)[Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
        start local 1 // java.lang.Object[] array
         0: .line 292
            aload 0 /* this */
            aload 1 /* array */
            invokevirtual com.google.common.collect.AbstractBiMap$ValueSet.standardToArray:([Ljava/lang/Object;)[Ljava/lang/Object;
            areturn
        end local 1 // java.lang.Object[] array
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    1     0   this  Lcom/google/common/collect/AbstractBiMap$ValueSet;
            0    1     1  array  [Ljava/lang/Object;
    Signature: <T:Ljava/lang/Object;>([TT;)[TT;
    MethodParameters:
       Name  Flags
      array  

  public java.lang.String toString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
         0: .line 297
            aload 0 /* this */
            invokevirtual com.google.common.collect.AbstractBiMap$ValueSet.standardToString:()Ljava/lang/String;
            areturn
        end local 0 // com.google.common.collect.AbstractBiMap$ValueSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/AbstractBiMap$ValueSet;

  protected java.lang.Object delegate();
    descriptor: ()Ljava/lang/Object;
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.collect.AbstractBiMap$ValueSet.delegate:()Ljava/util/Set;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  protected java.util.Collection delegate();
    descriptor: ()Ljava/util/Collection;
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.collect.AbstractBiMap$ValueSet.delegate:()Ljava/util/Set;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Lcom/google/common/collect/ForwardingSet<TV;>;
SourceFile: "AbstractBiMap.java"
NestHost: com.google.common.collect.AbstractBiMap
InnerClasses:
  private ValueSet = com.google.common.collect.AbstractBiMap$ValueSet of com.google.common.collect.AbstractBiMap
  public abstract Entry = java.util.Map$Entry of java.util.Map