Java reflection call default method from derived class

Question

from previous posts I figured out that the way to dynamically call a default method is the following:

final Class<?> declaringClass = method.getDeclaringClass();

final Constructor<Lookup> constructor =  
MethodHandles.Lookup.class.getDeclaredConstructor(Class.class, int.class);

constructor.setAccessible(true);

final MethodHandles.Lookup defaultMethodLookup =
                constructor.newInstance(declaringClass, MethodHandles.Lookup.PRIVATE);

return defaultMethodLookup
            .unreflectSpecial(method, declaringClass)
            .bindTo(proxy)
            .invokeWithArguments(args);

This works perfectly fine; however, if the call is from a derived interface which overrides the specific method, then the code above invokes the method of the base interface.

So, the problem is in the case that there is a default method on a base interface, let say ‘void fire()’, and a sub interface overrides this method, then the mechanism that invokes the default methods, invokes always only the one on the base class.

@waltersu its an argument to the `invoke` method of an invocation handler. The code above is inside an invocation handler. — theol.zacharopoulos, Jun 12 '16 at 10:11

score 0 · Answer 1 · answered Jun 17 '16 at 07:04

0

Just for the update, I managed to solve it differently. So, basically I keep track of the current object through its proxy, therefore I got the correct (derived) method through reflection and perform the MethodLookup on that, this worked fine. Thanks!

answered Jun 17 '16 at 07:04

theol.zacharopoulos

49
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Java reflection call default method from derived class

1 Answers1