### Question:
ISOMsgFieldValidatingPackager extends ISOMsgFieldPackager implements ISOValidator { public ISOComponent validate(ISOComponent m) throws ISOException { return ((ISOBaseValidatingPackager)msgPackager).validate( m ); } ISOMsgFieldValidatingPackager(
            ISOFieldPackager fieldPackager,
            ISOPackager msgPackager ); ISOComponent validate(ISOComponent m);  }### Answer:
@Test public void testValidateWithNonISOMsgThrowsNullPointerException() throws Throwable { try { new ISOMsgFieldValidatingPackager(new IFA_BINARY(100, "testISOMsgFieldValidatingPackagerDescription"), new ISOBaseValidatingPackager()).validate(new ISOField(100)); fail("Expected ClassCastException to be thrown"); } catch (NullPointerException ex) { assertEquals(NullPointerException.class, ex.getClass(), "ex.getClass()"); } }
@Test public void testValidateThrowsNullPointerException() throws Throwable { try { new ISOMsgFieldValidatingPackager(new IFB_AMOUNT(100, "testISOMsgFieldValidatingPackagerDescription", true), new ISOBaseValidatingPackager()).validate(new ISOMsg("testISOMsgFieldValidatingPackagerMti")); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot read the array length because \"<local6>\" is null", ex.getMessage(), "ex.getMessage()"); } } }