Convert java Calendar object from local time to UTC

Question

How do I convert a Java Calendar object from local time to UTC? This what I have tried:

    Calendar calendar = Calendar.getInstance();
    calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
    calendar.setTime(localDateTime.getTime());
    SimpleDateFormat outputFmt = new SimpleDateFormat("MMM dd, yyy h:mm a zz");
    String dateAsString = outputFmt.format(calendar.getTime());
    System.out.println(dateAsString)

Time is always displayed in MT not GMT. I want to store the calendar in UTC in a database (I'm not concerned with formatting or displaying the time).

Answer 1

You need call setTimeZone on SimpleDateFormat, not on Calendar :

//getting local time 
Calendar calendar = Calendar.getInstance(Locale.getDefault());

SimpleDateFormat outputFmt = new SimpleDateFormat("MMM dd, yyy h:mm a zz");
outputFmt.setTimeZone(TimeZone.getTimeZone("GMT")); //set timezone here

//shows calendar time correctly set    
System.out.println(outputFmt.format(calendar.getTime()));