Objects { public static boolean equals(Object o1, Object o2) { return o1 == null ? o2 == null : o1.equals(o2); }  static int hashCode(Object obj); static boolean equals(Object o1, Object o2); static boolean in(Object obj, Object... array);  }
@Test public void testEquals() { assertTrue(Objects.equals(null, null)); assertFalse(Objects.equals(null, "")); assertFalse(Objects.equals("", null)); assertTrue(Objects.equals("", "")); }