java.text.SimpleDateFormat not thread safe

Question

Synchronization

Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concur         


        

Answer 1

That's true. You can find already questions concerning this issue on StackOverflow. I use to declare it as ThreadLocal:

private static final ThreadLocal THREAD_LOCAL_DATEFORMAT = new ThreadLocal() {
    protected DateFormat initialValue() {
        return new SimpleDateFormat("yyyyMMdd");
    }
};

and in the code:

DateFormat df = THREAD_LOCAL_DATEFORMAT.get();