Synchronize SimpleDateFormat object in Java

SimpleDateFormat object does not work properly in a multi threaded environment. It may output a wrong date when parsing. So the safest way is to synchronize it.

private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
public String formatDate(Date d) {
    synchronized(sdf) {
        return sdf.format(d);
    }
}

Hope that help.