Here you can find the source of getCharStack()
public static Stack<Integer> getCharStack()
//package com.java2s; /*//from w w w . j av a 2s .c o m * Copyright (C) 2012 Ren? Jeschke <rene_jeschke@yahoo.de> * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License 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.util.Stack; public class Main { private final static ThreadLocal<Stack<Integer>> charStack = new ThreadLocal<Stack<Integer>>() { @Override protected java.util.Stack<Integer> initialValue() { return new Stack<Integer>(); } }; public static Stack<Integer> getCharStack() { return charStack.get(); } }