changing timzone using calender api

[nancy andrew]

I am trying to change timezone to EST (New York) time. But the below code still give me time in GMT. Kindly help me. My code is below

		 Calendar now = Calendar.getInstance();
		 now.setTimeZone(TimeZone.getTimeZone("America/New_York"));
		 //2009-11-24 15:40:00.0
		 SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.S");
		 System.out.println("Today's date is:::"+ formatter.format(now.getTime()));

[Mohamed Sanaulla]

Use a format in SimpleDateFormat which supports TimeZone.

[nancy andrew]

My code started working when i removed the formatter

		 Calendar now = Calendar.getInstance();
		 now.setTimeZone(TimeZone.getTimeZone("America/New_York"));		 
		String toDate = now.get(Calendar.YEAR)+"-"+(now.get(Calendar.MONTH) + 1)+"-"+now.get(Calendar.DATE)+" "+now.get(Calendar.HOUR)+":"+
		 		now.get(Calendar.MINUTE)+":"+now.get(Calendar.SECOND)+"."+now.get(Calendar.MILLISECOND);
		System.out.println("Today's date is:::"+ toDate);

But i have a question. Calender functionality takes the system date and converts it into a desired format. In case someone alters the system date then program will not give desired results. What can be done so that it takes date , say from internet server or some other place. What changes we need to make to the above code

[Mohamed Sanaulla]

The code worked because the format specified in the SimpleDateFormat didnt support Timezone information. You need to add "z" at the end of the string passed to SimpleDateFormat for timezone information to be shown.

Please start a new thread for a new question. (There should be some API available, not sure if its in JDK, to get the correct time from the Internet).

[M Massa]

I believe you could have set the time zone on the SimpleDateFormat instead of the Calendar object to display correctly.

Calendar now = Calendar.getInstance();  
//2009-11-24 15:40:00.0  
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.S");  
formatter.setTimeZone(TimeZone.getTimeZone("America/New_York"));
System.out.println("Today's date is:::"+ formatter.format(now.getTime()));  

[Jacob Anawalt]

Setting the formatter's calendar's timezone like that seems cleanest and side-effect free. If you want to use the timezone of a passed calendar, be safe and clone:

Calendar now = Calendar.getInstance();  
now.setTimeZone(TimeZone.getTimeZone("America/New_York"));  
//2009-11-24 15:40:00.0  
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.S");  
formatter.setCalendar((Calendar)now.clone());
System.out.println("Today's date is:::"+ formatter.format(now.getTime()));  

This is a pretty good resource for common mistakes with calendars and formatters: http://www.odi.ch/prog/design/datetime.php