Here you can find the source of format(Date date)
public static String format(Date date)
//package com.java2s; //License from project: Apache License import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Locale; import java.util.TimeZone; public class Main { /**/*from w ww .j a v a 2 s.com*/ * RFC822 5. DATE AND TIME SPECIFICATION */ static final String RFC1123_DATEFORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz"; static final TimeZone GMT = TimeZone.getTimeZone("GMT"); public static String format(Date date) { DateFormat fmt = newGMTFormatter(); return fmt.format(date); } public static DateFormat newGMTFormatter() { SimpleDateFormat fmt = new SimpleDateFormat(RFC1123_DATEFORMAT, Locale.ENGLISH); fmt.setTimeZone(GMT); return fmt; } }