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.Multisets$1 extends com.google.common.collect.Multisets$ViewMultiset<E>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.Multisets$1
  super_class: com.google.common.collect.Multisets$ViewMultiset
{
  private final com.google.common.collect.Multiset val$multiset1;
    descriptor: Lcom/google/common/collect/Multiset;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  private final com.google.common.collect.Multiset val$multiset2;
    descriptor: Lcom/google/common/collect/Multiset;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.google.common.collect.Multiset, com.google.common.collect.Multiset);
    descriptor: (Lcom/google/common/collect/Multiset;Lcom/google/common/collect/Multiset;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // com.google.common.collect.Multisets$1 this
         0: .line 412
            aload 0 /* this */
            aload 1
            putfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            aload 0 /* this */
            aload 2
            putfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            aload 0 /* this */
            invokespecial com.google.common.collect.Multisets$ViewMultiset.<init>:()V
            return
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$1;
    MethodParameters:
               Name  Flags
      val$multiset1  final
      val$multiset2  final

  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$1 this
        start local 1 // java.lang.Object element
         0: .line 415
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            aload 1 /* element */
            invokeinterface com.google.common.collect.Multiset.contains:(Ljava/lang/Object;)Z
            ifne 1
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            aload 1 /* element */
            invokeinterface com.google.common.collect.Multiset.contains:(Ljava/lang/Object;)Z
            ifne 1
            iconst_0
            ireturn
      StackMap locals:
      StackMap stack:
         1: iconst_1
            ireturn
        end local 1 // java.lang.Object element
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    2     0     this  Lcom/google/common/collect/Multisets$1;
            0    2     1  element  Ljava/lang/Object;
    RuntimeVisibleTypeAnnotations: 
      METHOD_FORMAL_PARAMETER
        org.checkerframework.checker.nullness.qual.Nullable()
    MethodParameters:
         Name  Flags
      element  

  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$1 this
         0: .line 420
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.isEmpty:()Z
            ifeq 1
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.isEmpty:()Z
            ifeq 1
            iconst_1
            ireturn
      StackMap locals:
      StackMap stack:
         1: iconst_0
            ireturn
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/collect/Multisets$1;

  public int count(java.lang.Object);
    descriptor: (Ljava/lang/Object;)I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.google.common.collect.Multisets$1 this
        start local 1 // java.lang.Object element
         0: .line 425
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            aload 1 /* element */
            invokeinterface com.google.common.collect.Multiset.count:(Ljava/lang/Object;)I
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            aload 1 /* element */
            invokeinterface com.google.common.collect.Multiset.count:(Ljava/lang/Object;)I
            invokestatic java.lang.Math.max:(II)I
            ireturn
        end local 1 // java.lang.Object element
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    1     0     this  Lcom/google/common/collect/Multisets$1;
            0    1     1  element  Ljava/lang/Object;
    MethodParameters:
         Name  Flags
      element  

  java.util.Set<E> createElementSet();
    descriptor: ()Ljava/util/Set;
    flags: (0x0000) 
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$1 this
         0: .line 430
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.elementSet:()Ljava/util/Set;
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.elementSet:()Ljava/util/Set;
            invokestatic com.google.common.collect.Sets.union:(Ljava/util/Set;Ljava/util/Set;)Lcom/google/common/collect/Sets$SetView;
            areturn
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$1;
    Signature: ()Ljava/util/Set<TE;>;

  java.util.Iterator<E> elementIterator();
    descriptor: ()Ljava/util/Iterator;
    flags: (0x0000) 
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // com.google.common.collect.Multisets$1 this
         0: .line 435
            new java.lang.AssertionError
            dup
            ldc "should never be called"
            invokespecial java.lang.AssertionError.<init>:(Ljava/lang/Object;)V
            athrow
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Multisets$1;
    Signature: ()Ljava/util/Iterator<TE;>;

  java.util.Iterator<com.google.common.collect.Multiset$Entry<E>> entryIterator();
    descriptor: ()Ljava/util/Iterator;
    flags: (0x0000) 
    Code:
      stack=7, locals=3, args_size=1
        start local 0 // com.google.common.collect.Multisets$1 this
         0: .line 440
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.entrySet:()Ljava/util/Set;
            invokeinterface java.util.Set.iterator:()Ljava/util/Iterator;
            astore 1 /* iterator1 */
        start local 1 // java.util.Iterator iterator1
         1: .line 441
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            invokeinterface com.google.common.collect.Multiset.entrySet:()Ljava/util/Set;
            invokeinterface java.util.Set.iterator:()Ljava/util/Iterator;
            astore 2 /* iterator2 */
        start local 2 // java.util.Iterator iterator2
         2: .line 443
            new com.google.common.collect.Multisets$1$1
            dup
            aload 0 /* this */
            aload 1 /* iterator1 */
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset2:Lcom/google/common/collect/Multiset;
            aload 2 /* iterator2 */
            aload 0 /* this */
            getfield com.google.common.collect.Multisets$1.val$multiset1:Lcom/google/common/collect/Multiset;
            invokespecial com.google.common.collect.Multisets$1$1.<init>:(Lcom/google/common/collect/Multisets$1;Ljava/util/Iterator;Lcom/google/common/collect/Multiset;Ljava/util/Iterator;Lcom/google/common/collect/Multiset;)V
            areturn
        end local 2 // java.util.Iterator iterator2
        end local 1 // java.util.Iterator iterator1
        end local 0 // com.google.common.collect.Multisets$1 this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    3     0       this  Lcom/google/common/collect/Multisets$1;
            1    3     1  iterator1  Ljava/util/Iterator<+Lcom/google/common/collect/Multiset$Entry<+TE;>;>;
            2    3     2  iterator2  Ljava/util/Iterator<+Lcom/google/common/collect/Multiset$Entry<+TE;>;>;
    Signature: ()Ljava/util/Iterator<Lcom/google/common/collect/Multiset$Entry<TE;>;>;
}
Signature: Lcom/google/common/collect/Multisets$ViewMultiset<TE;>;
SourceFile: "Multisets.java"
EnclosingMethod: com.google.common.collect.Multisets.union:(Lcom/google/common/collect/Multiset;Lcom/google/common/collect/Multiset;)Lcom/google/common/collect/Multiset;
NestHost: com.google.common.collect.Multisets
InnerClasses:
  public abstract Entry = com.google.common.collect.Multiset$Entry of com.google.common.collect.Multiset
  com.google.common.collect.Multisets$1
  com.google.common.collect.Multisets$1$1
  private abstract ViewMultiset = com.google.common.collect.Multisets$ViewMultiset of com.google.common.collect.Multisets
  public abstract SetView = com.google.common.collect.Sets$SetView of com.google.common.collect.Sets