public static void main(String[] args) { String str1 = "hello"; String str2 = new String("hello"); System.out.println(str1.equals(str2)); System.out.println(str1.intern() == str2.intern()); Date now = new Date(); Calendar calendar = Calendar.getInstance(); System.out.println(calendar.getMinimalDaysInFirstWeek()); // calendar.setFirstDayOfWeek(Calendar.MONDAY); calendar.setTime(now); calendar.add(Calendar.DATE, 144); System.out.println(calendar.getTime()); String burepayDay = new SimpleDateFormat("YYYYÄêMMÔÂddÈÕ").format(calendar.getTime()); System.out.println(calendar.getTime().toLocaleString()); System.out.println(burepayDay); System.out.println(calendar.getWeeksInWeekYear()); String str = "hjjk"; System.out.println(str.substring(0, 4)); }