Here you can find the source of valueOf(String s)
public static Boolean valueOf(String s)
//package com.java2s; /*//from ww w . j a va 2 s . c om * Copyright 2007 Google Inc. * * 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. */ public class Main { public static final Boolean FALSE = false; public static final Boolean TRUE = true; public static Boolean valueOf(boolean b) { return b ? TRUE : FALSE; } public static Boolean valueOf(String s) { return valueOf(parseBoolean(s)); } public static boolean parseBoolean(String s) { return "true".equalsIgnoreCase(s); } }