Date Conversion with ThreadLocal

Question

I have a requirement to convert incoming date string format \"20130212\" (YYYYMMDD) to 12/02/2013 (DD/MM/YYYY)

using ThreadLocal. I know a way to do th

Answer 1

ThreadLocal in Java is a way to achieve thread-safety apart from writing immutable classes. Since SimpleDateFormat is not thread safe, you can use a ThreadLocal to make it thread safe.

class DateFormatter{

    private static ThreadLocal outDateFormatHolder = new ThreadLocal() {
    @Override
    protected SimpleDateFormat initialValue() {
        return new SimpleDateFormat("MM/dd/yyyy");
    }
};

private static ThreadLocal inDateFormatHolder = new ThreadLocal() {
    @Override
    protected SimpleDateFormat initialValue() {
        return new SimpleDateFormat("yyyyMMdd");
    }
};

public static String formatDate(String date) throws ParseException { 
    return outDateFormatHolder.get().format(
            inDateFormatHolder.get().parse(date));
}        
}