https://www.graalvm.org/ 
public interface com.oracle.truffle.api.test.host.CallbackConvertTest$CallWithChar
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.api.test.host.CallbackConvertTest$CallWithChar
  super_class: java.lang.Object
{
  public abstract void callback(char);
    descriptor: (C)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      v     
}
SourceFile: "CallbackConvertTest.java"
NestHost: com.oracle.truffle.api.test.host.CallbackConvertTest
InnerClasses:
  public abstract CallWithChar = com.oracle.truffle.api.test.host.CallbackConvertTest$CallWithChar of com.oracle.truffle.api.test.host.CallbackConvertTest
  public abstract Implementable = org.graalvm.polyglot.HostAccess$Implementable of org.graalvm.polyglot.HostAccess
    RuntimeVisibleAnnotations: 
      org.graalvm.polyglot.HostAccess$Implementable()