https://www.graalvm.org/ 
public interface com.oracle.truffle.api.test.polyglot.ExposeToGuestTest$FooInterface<T extends java.lang.Number>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.oracle.truffle.api.test.polyglot.ExposeToGuestTest$FooInterface
  super_class: java.lang.Object
{
  public abstract  foo(T);
    descriptor: (Ljava/lang/Number;)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TT;)Ljava/lang/Object;
    RuntimeVisibleAnnotations: 
      org.graalvm.polyglot.HostAccess$Export()
    MethodParameters:
       Name  Flags
      value  
}
Signature: <T:Ljava/lang/Number;>Ljava/lang/Object;
SourceFile: "ExposeToGuestTest.java"
NestHost: com.oracle.truffle.api.test.polyglot.ExposeToGuestTest
InnerClasses:
  public abstract FooInterface = com.oracle.truffle.api.test.polyglot.ExposeToGuestTest$FooInterface of com.oracle.truffle.api.test.polyglot.ExposeToGuestTest
  public abstract Export = org.graalvm.polyglot.HostAccess$Export of org.graalvm.polyglot.HostAccess
    RuntimeVisibleAnnotations: 
      java.lang.FunctionalInterface()