static boolean empty(String s) {
        return (s == null || s.equals(""));
    }
@Test
    public void testEmpty() {
        assertTrue(LogUtil.empty(null));
        assertTrue(LogUtil.empty(""));
        assertFalse(LogUtil.empty("f"));
        assertFalse(LogUtil.empty("fo"));
        assertFalse(LogUtil.empty("foo"));
    }