### Question:
DateHelper { public static String getDatetime(long timestamp) { return getDatetime("yyyy-MM-dd HH:mm:ss", timestamp); }  static boolean containsDate(String searchString); static String getCurrentDatetime(String format); static String getDatetime(long timestamp); static String getDatetime(String format, long timestamp); static long getTimeOfDay(Date date, int resolution); static long getTimeOfDay(long timestamp, int resolution); static String getCurrentDatetime(); static int monthNameToNumber(String monthName); static String formatDuration(long startTime); static String formatDuration(long startTime, long stopTime); static String formatDuration(long startTime, long stopTime, boolean compact); static long getIntervalLength(Date intervalStartTime, Date intervalStopTime); static String getTimeString(long time); static Date validateYear(Date date); static long getMillisecondsToNextDay(); static void main(String[] t);  }### Answer:
@Test public void testGetDatetime() { assertEquals("20.05.2010", DateHelper.getDatetime("dd.MM.yyyy", 1274313600000l)); }