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.Streams$DoubleFunctionWithIndex<R>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.google.common.collect.Streams$DoubleFunctionWithIndex
  super_class: java.lang.Object
{
  public abstract R apply(double, );
    descriptor: (DJ)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (DJ)TR;
    MethodParameters:
       Name  Flags
      from   
      index  
}
Signature: <R:Ljava/lang/Object;>Ljava/lang/Object;
SourceFile: "Streams.java"
NestHost: com.google.common.collect.Streams
InnerClasses:
  public abstract DoubleFunctionWithIndex = com.google.common.collect.Streams$DoubleFunctionWithIndex of com.google.common.collect.Streams
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.Beta()