### Question:
DateDetector { public static boolean isValidDate( String dateString, String dateFormat ) { try { getDateFromStringByFormat( dateString, dateFormat ); return true; } catch ( ParseException e ) { return false; } } private  DateDetector(); static String getRegexpByDateFormat( String dateFormat ); static String getRegexpByDateFormat( String dateFormat, String locale ); static String getDateFormatByRegex( String regex ); static String getDateFormatByRegex( String regex, String locale ); static Date getDateFromString( String dateString ); static Date getDateFromString( String dateString, String locale ); static Date getDateFromStringByFormat( String dateString, String dateFormat ); static String detectDateFormat( String dateString ); static String detectDateFormat( String dateString, String locale ); static String detectDateFormatBiased( String dateString, String locale, String desiredKey ); static BidiMap getDateFormatToRegExps( String locale ); static boolean isValidDate( String dateString, String dateFormat ); static boolean isValidDate( String dateString ); static boolean isValidDateFormatToStringDate( String dateFormat, String dateString ); static boolean isValidDateFormatToStringDate( String dateFormat, String dateString, String locale );  }### Answer:
@Test public void testIsValidDate() { assertTrue( DateDetector.isValidDate( SAMPLE_DATE_STRING_US ) ); assertFalse( DateDetector.isValidDate( null ) ); assertTrue( DateDetector.isValidDate( SAMPLE_DATE_STRING, SAMPLE_DATE_FORMAT ) ); assertFalse( DateDetector.isValidDate( SAMPLE_DATE_STRING, null ) ); }