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