Here you can find the source of getHttpDateFormatter()
public static SimpleDateFormat getHttpDateFormatter()
//package com.java2s; //License from project: Apache License import java.text.SimpleDateFormat; import java.util.*; public class Main { private static ThreadLocal<SimpleDateFormat> httpFormatter = new ThreadLocal<SimpleDateFormat>(); public static SimpleDateFormat getHttpDateFormatter() { if (httpFormatter.get() == null) { httpFormatter.set(new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)); httpFormatter.get().setTimeZone(TimeZone.getTimeZone("GMT")); }/* w w w.j av a 2 s.co m*/ return httpFormatter.get(); } }