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. 
abstract class com.google.common.collect.Multisets$ElementSet<E> extends com.google.common.collect.Sets$ImprovedAbstractSet<E>
  minor version: 0
  major version: 59
  flags: flags: (0x0420) ACC_SUPER, ACC_ABSTRACT
  this_class: com.google.common.collect.Multisets$ElementSet
  super_class: com.google.common.collect.Sets$ImprovedAbstractSet
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$ElementSet this
         0: .line 970
            aload 0 /* this */
            invokespecial com.google.common.collect.Sets$ImprovedAbstractSet.<init>:()V
            return
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;

  abstract com.google.common.collect.Multiset<E> multiset();
    descriptor: ()Lcom/google/common/collect/Multiset;
    flags: (0x0400) ACC_ABSTRACT
    Signature: ()Lcom/google/common/collect/Multiset<TE;>;

  public void clear();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$ElementSet this
         0: .line 975
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.clear:()V
         1: .line 976
            return
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;

  public boolean contains(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.collect.Multisets$ElementSet this
        start local 1 // java.lang.Object o
         0: .line 980
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            aload 1 /* o */
            invokeinterface com.google.common.collect.Multiset.contains:(Ljava/lang/Object;)Z
            ireturn
        end local 1 // java.lang.Object o
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;
            0    1     1     o  Ljava/lang/Object;
    MethodParameters:
      Name  Flags
      o     

  public boolean containsAll(java.util.Collection<?>);
    descriptor: (Ljava/util/Collection;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.collect.Multisets$ElementSet this
        start local 1 // java.util.Collection c
         0: .line 985
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            aload 1 /* c */
            invokeinterface com.google.common.collect.Multiset.containsAll:(Ljava/util/Collection;)Z
            ireturn
        end local 1 // java.util.Collection c
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;
            0    1     1     c  Ljava/util/Collection<*>;
    Signature: (Ljava/util/Collection<*>;)Z
    MethodParameters:
      Name  Flags
      c     

  public boolean isEmpty();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$ElementSet this
         0: .line 990
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.isEmpty:()Z
            ireturn
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;

  public abstract java.util.Iterator<E> iterator();
    descriptor: ()Ljava/util/Iterator;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()Ljava/util/Iterator<TE;>;

  public boolean remove(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.google.common.collect.Multisets$ElementSet this
        start local 1 // java.lang.Object o
         0: .line 998
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            aload 1 /* o */
            ldc 2147483647
            invokeinterface com.google.common.collect.Multiset.remove:(Ljava/lang/Object;I)I
            ifle 1
            iconst_1
            ireturn
      StackMap locals:
      StackMap stack:
         1: iconst_0
            ireturn
        end local 1 // java.lang.Object o
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;
            0    2     1     o  Ljava/lang/Object;
    MethodParameters:
      Name  Flags
      o     

  public int size();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$ElementSet this
         0: .line 1003
            aload 0 /* this */
            invokevirtual com.google.common.collect.Multisets$ElementSet.multiset:()Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.entrySet:()Ljava/util/Set;
            invokeinterface java.util.Set.size:()I
            ireturn
        end local 0 // com.google.common.collect.Multisets$ElementSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$ElementSet<TE;>;
}
Signature: <E:Ljava/lang/Object;>Lcom/google/common/collect/Sets$ImprovedAbstractSet<TE;>;
SourceFile: "Multisets.java"
NestHost: com.google.common.collect.Multisets
InnerClasses:
  public abstract Entry = com.google.common.collect.Multiset$Entry of com.google.common.collect.Multiset
  abstract ElementSet = com.google.common.collect.Multisets$ElementSet of com.google.common.collect.Multisets
  abstract ImprovedAbstractSet = com.google.common.collect.Sets$ImprovedAbstractSet of com.google.common.collect.Sets