How to convert date time from one time zone to another time zone

datetime, java, timezone

Solution

If you type in google "Java date change timezone" or "Javascript date change timezone". You will have one of your results:

In Java (source: http://www.coderanch.com/t/417443/java/java/Convert-Date-one-timezone-another )

Date date = new Date();  

DateFormat formatter = new SimpleDateFormat("dd MMM yyyy HH:mm:ss z");  
formatter.setTimeZone(TimeZone.getTimeZone("CET"));  

// Prints the date in the CET timezone  
System.out.println(formatter.format(date));  

// Set the formatter to use a different timezone  
formatter.setTimeZone(TimeZone.getTimeZone("IST"));  

// Prints the date in the IST timezone  
System.out.println(formatter.format(date));

Javascript (source: http://www.techrepublic.com/article/convert-the-local-time-to-another-time-zone-with-this-javascript/6016329 )

// function to calculate local time
// in a different city
// given the city's UTC offset
function calcTime(city, offset) {

    // create Date object for current location
    d = new Date();

    // convert to msec
    // add local time zone offset
    // get UTC time in msec
    utc = d.getTime() + (d.getTimezoneOffset() * 60000);

    // create new Date object for different city
    // using supplied offset
    nd = new Date(utc + (3600000*offset));

    // return time as a string
    return "The local time in " + city + " is " + nd.toLocaleString();

}

// get Bombay time
alert(calcTime('Bombay', '+5.5'));

Problem

The records are getting saved according to time zone of US but if I want to show the same record back to user it should convert the server date time with(US Time Zone) to user's date time with user's Time Zone

Original source