Here you can find the source of getFormat(String formatString)
private static DateFormat getFormat(String formatString)
//package com.java2s; /*/* w ww.j a va2s . c o m*/ * Copyright 2013-2015 EMC Corporation. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://www.apache.org/licenses/LICENSE-2.0.txt * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. */ import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.TimeZone; import java.util.WeakHashMap; public class Main { private static final ThreadLocal<WeakHashMap<String, DateFormat>> formatCache = new ThreadLocal<>(); private static DateFormat getFormat(String formatString) { if (formatCache.get() == null) { formatCache.set(new WeakHashMap<String, DateFormat>()); } DateFormat format = formatCache.get().get(formatString); if (format == null) { format = new SimpleDateFormat(formatString); format.setTimeZone(TimeZone.getTimeZone("UTC")); formatCache.get().put(formatString, format); } return format; } }