### Question:
AbstractType { public final boolean equals(Object x, Object y) throws HibernateException { if (x == y) { return true; } else if (x == null || y == null) { return false; } else { return x.equals(y); } }  final boolean equals(Object x, Object y); final int hashCode(Object value);  }### Answer:
@Test public void equality() { assertTrue(type.equals(null, null)); assertFalse(type.equals(serializable, null)); assertFalse(type.equals(null, serializable)); assertTrue(type.equals(serializable, serializable)); }