### Question:
ObjectUtil { public static boolean equals(Object object1, Object object2) { if (object1 == object2) { return true; } if ((object1 == null) || (object2 == null)) { return false; } return object1.equals(object2); }  static boolean equals(Object object1, Object object2); static T requireNonNull(T obj, String message); static void requireNotEmpty(String str, String message);  }### Answer:
@Test public void testEquals() { String a = new String("a"); String b = new String("b"); assertFalse(ObjectUtil.equals(b, a)); assertFalse(ObjectUtil.equals(a, b)); assertFalse(ObjectUtil.equals(a, null)); assertFalse(ObjectUtil.equals(null, a)); assertTrue(ObjectUtil.equals(null, null)); assertTrue(ObjectUtil.equals(a, a)); }