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. 
public abstract class com.google.common.collect.ForwardingIterator<T> extends com.google.common.collect.ForwardingObject implements java.util.Iterator<T>
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: com.google.common.collect.ForwardingIterator
  super_class: com.google.common.collect.ForwardingObject
{
  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingIterator this
         0: .line 42
            aload 0 /* this */
            invokespecial com.google.common.collect.ForwardingObject.<init>:()V
            return
        end local 0 // com.google.common.collect.ForwardingIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/ForwardingIterator<TT;>;

  protected abstract java.util.Iterator<T> delegate();
    descriptor: ()Ljava/util/Iterator;
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
    Signature: ()Ljava/util/Iterator<TT;>;

  public boolean hasNext();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingIterator this
         0: .line 49
            aload 0 /* this */
            invokevirtual com.google.common.collect.ForwardingIterator.delegate:()Ljava/util/Iterator;
            invokeinterface java.util.Iterator.hasNext:()Z
            ireturn
        end local 0 // com.google.common.collect.ForwardingIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/ForwardingIterator<TT;>;

  public T next();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingIterator this
         0: .line 55
            aload 0 /* this */
            invokevirtual com.google.common.collect.ForwardingIterator.delegate:()Ljava/util/Iterator;
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            areturn
        end local 0 // com.google.common.collect.ForwardingIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/ForwardingIterator<TT;>;
    Signature: ()TT;
    RuntimeInvisibleAnnotations: 
      com.google.errorprone.annotations.CanIgnoreReturnValue()

  public void remove();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.ForwardingIterator this
         0: .line 60
            aload 0 /* this */
            invokevirtual com.google.common.collect.ForwardingIterator.delegate:()Ljava/util/Iterator;
            invokeinterface java.util.Iterator.remove:()V
         1: .line 61
            return
        end local 0 // com.google.common.collect.ForwardingIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/collect/ForwardingIterator<TT;>;

  protected java.lang.Object delegate();
    descriptor: ()Ljava/lang/Object;
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.collect.ForwardingIterator.delegate:()Ljava/util/Iterator;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: <T:Ljava/lang/Object;>Lcom/google/common/collect/ForwardingObject;Ljava/util/Iterator<TT;>;
SourceFile: "ForwardingIterator.java"
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.GwtCompatible()