https://github.com/eclipse/eclipse-collections/eclipse-collections-api: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar
  • Sirisha Pratha 
public interface org.eclipse.collections.api.block.function.Function2<T1, T2, R> extends java.util.function.BiFunction<T1, T2, R>, java.io.Serializable
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.eclipse.collections.api.block.function.Function2
  super_class: java.lang.Object
{
  public abstract R value(T1, );
    descriptor: (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TT1;TT2;)TR;
    MethodParameters:
           Name  Flags
      argument1  
      argument2  

  public R apply(T1, );
    descriptor: (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // org.eclipse.collections.api.block.function.Function2 this
        start local 1 // java.lang.Object argument1
        start local 2 // java.lang.Object argument2
         0: .line 35
            aload 0 /* this */
            aload 1 /* argument1 */
            aload 2 /* argument2 */
            invokeinterface org.eclipse.collections.api.block.function.Function2.value:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
            areturn
        end local 2 // java.lang.Object argument2
        end local 1 // java.lang.Object argument1
        end local 0 // org.eclipse.collections.api.block.function.Function2 this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    1     0       this  Lorg/eclipse/collections/api/block/function/Function2<TT1;TT2;TR;>;
            0    1     1  argument1  TT1;
            0    1     2  argument2  TT2;
    Signature: (TT1;TT2;)TR;
    MethodParameters:
           Name  Flags
      argument1  
      argument2  
}
Signature: <T1:Ljava/lang/Object;T2:Ljava/lang/Object;R:Ljava/lang/Object;>Ljava/lang/Object;Ljava/util/function/BiFunction<TT1;TT2;TR;>;Ljava/io/Serializable;
SourceFile: "Function2.java"
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()