Util { public static boolean isBlank(String s) { return s == null || s.isEmpty(); } private  Util(); static void sleep(long ms); static boolean wildcardMatch(String text, String pattern); static boolean isBlank(String s);  }
@Test public void testIsBlank() { assertTrue(Util.isBlank("")); assertTrue(Util.isBlank(null)); assertFalse(Util.isBlank("Not blank")); }