https://www.graalvm.org/ 
public interface com.oracle.truffle.api.test.polyglot.ValueAPITest$ExecutableInterface
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.api.test.polyglot.ValueAPITest$ExecutableInterface
  super_class: java.lang.Object
{
  public abstract java.lang.String execute(java.lang.String);
    descriptor: (Ljava/lang/String;)Ljava/lang/String;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
          Name  Flags
      argument  
}
SourceFile: "ValueAPITest.java"
NestHost: com.oracle.truffle.api.test.polyglot.ValueAPITest
InnerClasses:
  public abstract ExecutableInterface = com.oracle.truffle.api.test.polyglot.ValueAPITest$ExecutableInterface of com.oracle.truffle.api.test.polyglot.ValueAPITest
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()