Convert BoundMethodHandle to reflection

Question

Is it possible to retrieve the member that is being referenced to with a MethodHandle?

MethodHandle mh = MethodHandles.lookup().findStatic(..., ..., ...);
java.lang.reflect.Method method = convertToReflection(mn); //???

Answer 1

The correct term is “direct method handle”, to emphasize the fact that there is a direct connection to a member of a class. Or as the documentation puts it:

A direct method handle represents a method, constructor, or field without any intervening argument bindings or other transformations.

The term “bound” would rather suggest that there are pre-bound parameter values or a bound receiver, which would not match a plain Reflection object anymore.

Java 8 allows to get the member from a MethodHandle via MethodHandles.Lookup.revealDirect(…):

public class Tmp {
    public static void main(String[] args) throws ReflectiveOperationException {
        MethodHandles.Lookup lookup = MethodHandles.lookup();
        MethodHandle mh = lookup
          .findStatic(Tmp.class, "main", MethodType.methodType(void.class, String[].class));
        Method method = lookup.revealDirect(mh).reflectAs(Method.class, lookup);
        System.out.println(method);
    }
}

It’s constrained to Reflection objects compatible with the context described by the Lookup object you provide, i.e. it will work when trying to lookup the same member via name & type would succeed with that lookup object.