views:

226

answers:

1

I'm getting an IllegalArgumentException, but I can't figure out why.

The function I'm trying to access:

private static Player checkEvents(Player[] players, GameMaster bananas)

The problematic code:

@Test
public void testCheckEvents() throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {
 Game g = new Game();
 GameMaster gm = new GameMaster(4);
 Player[] p = new Player[] {new Player(gm), new Player(gm), new Player(gm), new Player(gm)};

 Method checkEvents = g.getClass().getDeclaredMethod("checkEvents", new Class[] {p.getClass(), GameMaster.class});
 checkEvents.setAccessible(true);

 checkEvents.invoke(p, gm); // fails here
}

The failure:

testCheckEvents(nth.bananas.GameTest)
java.lang.IllegalArgumentException: wrong number of arguments

What am I doing wrong?

+4  A: 

The first argument to invoke must be an object on which to invoke the method:

checkEvents.invoke(g, p, gm)

Since your method is static, you can also use null instead of the object reference g.

hjhill
To expand on @hjhill's correct answer, if the Method object refers to a static method, the first argument of invoke() is ignored.
Jim Garrison