https://www.graalvm.org/ 
interface com.oracle.truffle.polyglot.PolyglotThread$PolyglotThreadRunnable
  minor version: 0
  major version: 59
  flags: flags: (0x0600) ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.polyglot.PolyglotThread$PolyglotThreadRunnable
  super_class: java.lang.Object
{
  public abstract void execute();
    descriptor: ()V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "PolyglotThread.java"
NestHost: com.oracle.truffle.polyglot.PolyglotThread
InnerClasses:
  private abstract PolyglotThreadRunnable = com.oracle.truffle.polyglot.PolyglotThread$PolyglotThreadRunnable of com.oracle.truffle.polyglot.PolyglotThread