A DESCRIPTION OF THE PROBLEM :
Unable to call default method from interface in an other module from named module.

Using Lookup.findSpecial it is possible to get a MethodHandle for the default method of an interface.
This only works if the code is in an unnamed module.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to find a MethodHandle for a default method of an interface in an other module from a named module.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A MethodHandle for the default method is returned.
ACTUAL -
An exception is thrown.

---------- BEGIN SOURCE ----------
package bug;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.reflect.Method;
import java.util.Comparator;

public class ModuleFindDefault {
private static final Lookup LOOKUP = MethodHandles.lookup();

public static void main(String[] args) throws Throwable {
Method method = Comparator.class.getMethod("reversed");
Comparator<Object> cmp = new TestInterf();

MethodHandle mhFind = findSpecial(method);
Object findRev = mhFind.invoke(cmp);
System.out.println(findRev);
}

static MethodHandle findSpecial(Method m) throws ReflectiveOperationException {
return LOOKUP.findSpecial(m.getDeclaringClass(), m.getName(),
MethodType.methodType(m.getReturnType(), m.getParameterTypes()),
m.getDeclaringClass());
}

static class TestInterf implements Comparator<Object> {

public int compare(Object o1, Object o2) {
return 0;
}

@Override
public Comparator<Object> reversed() {
System.out.println("ModuleFindDefault.TestInterf.reversed()");
return this;
}

}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Get somehow a private lookup in an unnamed module:

Create a ClassLoader, define a class, get the Lookup from this class?

FREQUENCY : always