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.Sets$4$1 extends com.google.common.collect.AbstractIterator<E>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.Sets$4$1
  super_class: com.google.common.collect.AbstractIterator
{
  final com.google.common.collect.Sets$4 this$1;
    descriptor: Lcom/google/common/collect/Sets$4;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  private final java.util.Iterator val$itr1;
    descriptor: Ljava/util/Iterator;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  private final java.util.Set val$set2;
    descriptor: Ljava/util/Set;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  private final java.util.Iterator val$itr2;
    descriptor: Ljava/util/Iterator;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  private final java.util.Set val$set1;
    descriptor: Ljava/util/Set;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.google.common.collect.Sets$4, java.util.Iterator, java.util.Set, java.util.Iterator, java.util.Set);
    descriptor: (Lcom/google/common/collect/Sets$4;Ljava/util/Iterator;Ljava/util/Set;Ljava/util/Iterator;Ljava/util/Set;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=6, args_size=6
        start local 0 // com.google.common.collect.Sets$4$1 this
         0: .line 973
            aload 0 /* this */
            aload 1
            putfield com.google.common.collect.Sets$4$1.this$1:Lcom/google/common/collect/Sets$4;
            aload 0 /* this */
            aload 2
            putfield com.google.common.collect.Sets$4$1.val$itr1:Ljava/util/Iterator;
            aload 0 /* this */
            aload 3
            putfield com.google.common.collect.Sets$4$1.val$set2:Ljava/util/Set;
            aload 0 /* this */
            aload 4
            putfield com.google.common.collect.Sets$4$1.val$itr2:Ljava/util/Iterator;
            aload 0 /* this */
            aload 5
            putfield com.google.common.collect.Sets$4$1.val$set1:Ljava/util/Set;
            aload 0 /* this */
            invokespecial com.google.common.collect.AbstractIterator.<init>:()V
            return
        end local 0 // com.google.common.collect.Sets$4$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/Sets$4$1;
    MethodParameters:
          Name  Flags
      this$0    final
      val$itr1  final
      val$set2  final
      val$itr2  final
      val$set1  final

  public E computeNext();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=1
        start local 0 // com.google.common.collect.Sets$4$1 this
         0: .line 976
            goto 4
         1: .line 977
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$itr1:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            astore 1 /* elem1 */
        start local 1 // java.lang.Object elem1
         2: .line 978
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$set2:Ljava/util/Set;
            aload 1 /* elem1 */
            invokeinterface java.util.Set.contains:(Ljava/lang/Object;)Z
            ifne 4
         3: .line 979
            aload 1 /* elem1 */
            areturn
        end local 1 // java.lang.Object elem1
         4: .line 976
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$itr1:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 1
         5: .line 982
            goto 9
         6: .line 983
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$itr2:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            astore 1 /* elem2 */
        start local 1 // java.lang.Object elem2
         7: .line 984
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$set1:Ljava/util/Set;
            aload 1 /* elem2 */
            invokeinterface java.util.Set.contains:(Ljava/lang/Object;)Z
            ifne 9
         8: .line 985
            aload 1 /* elem2 */
            areturn
        end local 1 // java.lang.Object elem2
         9: .line 982
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield com.google.common.collect.Sets$4$1.val$itr2:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 6
        10: .line 988
            aload 0 /* this */
            invokevirtual com.google.common.collect.Sets$4$1.endOfData:()Ljava/lang/Object;
            areturn
        end local 0 // com.google.common.collect.Sets$4$1 this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   11     0   this  Lcom/google/common/collect/Sets$4$1;
            2    4     1  elem1  TE;
            7    9     1  elem2  TE;
    Signature: ()TE;
}
Signature: Lcom/google/common/collect/AbstractIterator<TE;>;
SourceFile: "Sets.java"
EnclosingMethod: com.google.common.collect.Sets$4.iterator:()Lcom/google/common/collect/UnmodifiableIterator;
NestHost: com.google.common.collect.Sets
InnerClasses:
  com.google.common.collect.Sets$4
  com.google.common.collect.Sets$4$1