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 interface com.google.common.collect.PeekingIterator<E> extends java.util.Iterator<E>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.google.common.collect.PeekingIterator
  super_class: java.lang.Object
{
  public abstract E peek();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()TE;

  public abstract E next();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()TE;
    RuntimeInvisibleAnnotations: 
      com.google.errorprone.annotations.CanIgnoreReturnValue()

  public abstract void remove();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
Signature: <E:Ljava/lang/Object;>Ljava/lang/Object;Ljava/util/Iterator<TE;>;
SourceFile: "PeekingIterator.java"
    RuntimeVisibleAnnotations: 
      com.google.errorprone.annotations.DoNotMock(value = "Use Iterators.peekingIterator")
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.GwtCompatible()