### Question:
ErrorHandling { Optional<Integer> handleErrorByReturningOptionalInstance(String integer) { throw new UnsupportedOperationException("Delete this statement and write your own implementation."); }    }### Answer:
@Ignore("Remove to run test") @Test public void testReturnOptionalInstance() { Optional<Integer> successfulResult = errorHandling.handleErrorByReturningOptionalInstance("1"); assertTrue(successfulResult.isPresent()); assertEquals(1, (int) successfulResult.get()); Optional<Integer> failureResult = errorHandling.handleErrorByReturningOptionalInstance("a"); assertFalse(failureResult.isPresent()); }