### Question:
ObjectUtils { public static boolean eitherNull(Object obj1, Object obj2) { return obj1 == null || obj2 == null; }  static boolean bothNull(Object obj1, Object obj2); static boolean eitherNull(Object obj1, Object obj2); static boolean notEquals(Object obj1, Object obj2);  }### Answer:
@Test public void testEitherNull() { assertThat(ObjectUtils.eitherNull(null, null)).isTrue(); assertThat(ObjectUtils.eitherNull("", null)).isTrue(); assertThat(ObjectUtils.eitherNull(null, "")).isTrue(); assertThat(ObjectUtils.eitherNull("", "")).isFalse(); }