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

The idea behind this is that SimpleDateFormat is not thread-safe so in a mutil-threaded app you cannot share an instance of SimpleDateFormat between multiple threads. But since creation of SimpleDateFormat is an expensive operation we can use a ThreadLocal as workaround

static ThreadLocal format1 = new ThreadLocal() {
    @Override
    protected SimpleDateFormat initialValue() {
        return new SimpleDateFormat("yyyy-MM-dd");
    }
};

public String formatDate(Date date) {
    return format1.get().format(date);
}