Here you can find the source of addAll(S collection, T... values)
public final static <T, S extends Collection<T>> S addAll(S collection, T... values)
//package com.java2s; /*/*from w w w.j a v a2 s.c o m*/ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 2013-2020 Madz. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://raw.github.com/zhongdj/Lifecycle/master/License.txt * . See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at packager/legal/LICENSE.txt. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ import java.util.Arrays; import java.util.Collection; public class Main { /** * Add all elements to the collection */ // @SafeVarargs public final static <T, S extends Collection<T>> S addAll(S collection, T... values) { collection.addAll(Arrays.asList(values)); return collection; } }