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.cache.LocalCache$AbstractCacheSet<T> extends java.util.AbstractSet<T>
  minor version: 0
  major version: 59
  flags: flags: (0x0420) ACC_SUPER, ACC_ABSTRACT
  this_class: com.google.common.cache.LocalCache$AbstractCacheSet
  super_class: java.util.AbstractSet
{
  final com.google.common.cache.LocalCache this$0;
    descriptor: Lcom/google/common/cache/LocalCache;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.google.common.cache.LocalCache);
    descriptor: (Lcom/google/common/cache/LocalCache;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
         0: .line 4496
            aload 0 /* this */
            aload 1
            putfield com.google.common.cache.LocalCache$AbstractCacheSet.this$0:Lcom/google/common/cache/LocalCache;
            aload 0 /* this */
            invokespecial java.util.AbstractSet.<init>:()V
            return
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;
    MethodParameters:
        Name  Flags
      this$0  final

  public int size();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
         0: .line 4499
            aload 0 /* this */
            getfield com.google.common.cache.LocalCache$AbstractCacheSet.this$0:Lcom/google/common/cache/LocalCache;
            invokevirtual com.google.common.cache.LocalCache.size:()I
            ireturn
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;

  public boolean isEmpty();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
         0: .line 4504
            aload 0 /* this */
            getfield com.google.common.cache.LocalCache$AbstractCacheSet.this$0:Lcom/google/common/cache/LocalCache;
            invokevirtual com.google.common.cache.LocalCache.isEmpty:()Z
            ireturn
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;

  public void clear();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
         0: .line 4509
            aload 0 /* this */
            getfield com.google.common.cache.LocalCache$AbstractCacheSet.this$0:Lcom/google/common/cache/LocalCache;
            invokevirtual com.google.common.cache.LocalCache.clear:()V
         1: .line 4510
            return
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;

  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.cache.LocalCache$AbstractCacheSet this
         0: .line 4517
            aload 0 /* this */
            invokestatic com.google.common.cache.LocalCache.toArrayList:(Ljava/util/Collection;)Ljava/util/ArrayList;
            invokevirtual java.util.ArrayList.toArray:()[Ljava/lang/Object;
            areturn
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;

  public <E> E[] 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.cache.LocalCache$AbstractCacheSet this
        start local 1 // java.lang.Object[] a
         0: .line 4522
            aload 0 /* this */
            invokestatic com.google.common.cache.LocalCache.toArrayList:(Ljava/util/Collection;)Ljava/util/ArrayList;
            aload 1 /* a */
            invokevirtual java.util.ArrayList.toArray:([Ljava/lang/Object;)[Ljava/lang/Object;
            areturn
        end local 1 // java.lang.Object[] a
        end local 0 // com.google.common.cache.LocalCache$AbstractCacheSet this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/LocalCache<TK;TV;>.AbstractCacheSet<TT;>;
            0    1     1     a  [Ljava/lang/Object;
    Signature: <E:Ljava/lang/Object;>([TE;)[TE;
    MethodParameters:
      Name  Flags
      a     
}
Signature: <T:Ljava/lang/Object;>Ljava/util/AbstractSet<TT;>;
SourceFile: "LocalCache.java"
NestHost: com.google.common.cache.LocalCache
InnerClasses:
  abstract AbstractCacheSet = com.google.common.cache.LocalCache$AbstractCacheSet of com.google.common.cache.LocalCache