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.Streams$2 extends java.util.Spliterators$AbstractSpliterator<R>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.collect.Streams$2
  super_class: java.util.Spliterators$AbstractSpliterator
{
  long index;
    descriptor: J
    flags: (0x0000) 

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

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

  void <init>(long, int, java.util.Iterator, com.google.common.collect.Streams$FunctionWithIndex);
    descriptor: (JILjava/util/Iterator;Lcom/google/common/collect/Streams$FunctionWithIndex;)V
    flags: (0x0000) 
    Code:
      stack=4, locals=6, args_size=5
        start local 0 // com.google.common.collect.Streams$2 this
        start local 1 // long $anonymous0
        start local 3 // int $anonymous1
         0: .line 358
            aload 0 /* this */
            aload 4
            putfield com.google.common.collect.Streams$2.val$fromIterator:Ljava/util/Iterator;
            aload 0 /* this */
            aload 5
            putfield com.google.common.collect.Streams$2.val$function:Lcom/google/common/collect/Streams$FunctionWithIndex;
            aload 0 /* this */
            lload 1 /* $anonymous0 */
            iload 3 /* $anonymous1 */
            invokespecial java.util.Spliterators$AbstractSpliterator.<init>:(JI)V
         1: .line 361
            aload 0 /* this */
            lconst_0
            putfield com.google.common.collect.Streams$2.index:J
         2: .line 358
            return
        end local 3 // int $anonymous1
        end local 1 // long $anonymous0
        end local 0 // com.google.common.collect.Streams$2 this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    3     0         this  Lcom/google/common/collect/Streams$2;
            0    3     1  $anonymous0  J
            0    3     3  $anonymous1  I
    MethodParameters:
                  Name  Flags
      $anonymous0       
      $anonymous1       
      val$fromIterator  final
      val$function      final

  public boolean tryAdvance(java.util.function.Consumer<? super R>);
    descriptor: (Ljava/util/function/Consumer;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=10, locals=2, args_size=2
        start local 0 // com.google.common.collect.Streams$2 this
        start local 1 // java.util.function.Consumer action
         0: .line 365
            aload 0 /* this */
            getfield com.google.common.collect.Streams$2.val$fromIterator:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.hasNext:()Z
            ifeq 3
         1: .line 366
            aload 1 /* action */
            aload 0 /* this */
            getfield com.google.common.collect.Streams$2.val$function:Lcom/google/common/collect/Streams$FunctionWithIndex;
            aload 0 /* this */
            getfield com.google.common.collect.Streams$2.val$fromIterator:Ljava/util/Iterator;
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            aload 0 /* this */
            dup
            getfield com.google.common.collect.Streams$2.index:J
            dup2_x1
            lconst_1
            ladd
            putfield com.google.common.collect.Streams$2.index:J
            invokeinterface com.google.common.collect.Streams$FunctionWithIndex.apply:(Ljava/lang/Object;J)Ljava/lang/Object;
            invokeinterface java.util.function.Consumer.accept:(Ljava/lang/Object;)V
         2: .line 367
            iconst_1
            ireturn
         3: .line 369
      StackMap locals:
      StackMap stack:
            iconst_0
            ireturn
        end local 1 // java.util.function.Consumer action
        end local 0 // com.google.common.collect.Streams$2 this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    4     0    this  Lcom/google/common/collect/Streams$2;
            0    4     1  action  Ljava/util/function/Consumer<-TR;>;
    Signature: (Ljava/util/function/Consumer<-TR;>;)Z
    MethodParameters:
        Name  Flags
      action  
}
Signature: Ljava/util/Spliterators$AbstractSpliterator<TR;>;
SourceFile: "Streams.java"
EnclosingMethod: com.google.common.collect.Streams.mapWithIndex:(Ljava/util/stream/Stream;Lcom/google/common/collect/Streams$FunctionWithIndex;)Ljava/util/stream/Stream;
NestHost: com.google.common.collect.Streams
InnerClasses:
  com.google.common.collect.Streams$2
  public abstract FunctionWithIndex = com.google.common.collect.Streams$FunctionWithIndex of com.google.common.collect.Streams
  public abstract AbstractSpliterator = java.util.Spliterators$AbstractSpliterator of java.util.Spliterators