https://www.graalvm.org/ 
public interface com.oracle.truffle.js.test.interop.AsyncInteropTest$Executable
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.js.test.interop.AsyncInteropTest$Executable
  super_class: java.lang.Object
{
  public abstract void onPromiseCreation(org.graalvm.polyglot.Value, org.graalvm.polyglot.Value);
    descriptor: (Lorg/graalvm/polyglot/Value;Lorg/graalvm/polyglot/Value;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
           Name  Flags
      onResolve  
      onReject   
}
SourceFile: "AsyncInteropTest.java"
NestHost: com.oracle.truffle.js.test.interop.AsyncInteropTest
InnerClasses:
  public abstract Executable = com.oracle.truffle.js.test.interop.AsyncInteropTest$Executable of com.oracle.truffle.js.test.interop.AsyncInteropTest
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()