Automagic unit tests for upholding Object method contracts in Java?

Question

When developing Java applications, I often override Object methods (usually equals and hashCode). I would like some way to systematically check that I\'m adhering to the co

Answer 1

    public static void checkObjectIdentity(Object a1, Object a2, Object b1) {
        assertEquals(a1, a2);
        assertEquals(a2, a1);
        assertNotSame(a1, a2);
        assertEquals(a1.hashCode(), a2.hashCode());
        assertFalse(a1.equals(b1));
        assertFalse(a2.equals(b1));
        assertFalse(b1.equals(a1));
        assertFalse(b1.equals(a2));
    }

Usage:

        checkObjectIdentity(new Integer(3), new Integer(3), new Integer(4));

Can't think of anything better. Add new calls to checkObjectIdentity when you find a bug.