### Question:
ObjectUtils { public static boolean bothNull(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 testBothNull() { assertThat(ObjectUtils.bothNull(null, null)).isTrue(); assertThat(ObjectUtils.bothNull("", null)).isFalse(); assertThat(ObjectUtils.bothNull(null, "")).isFalse(); assertThat(ObjectUtils.bothNull("", "")).isFalse(); }