Here you can find the source of addAll(final Collection
@SafeVarargs public static <T> int addAll(final Collection<T> coll, final T... objs)
//package com.java2s; /*/* w w w . ja va 2 s. c o m*/ * Copyright 2002-2009 the original author or authors. * 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.Collection; public class Main { @SafeVarargs public static <T> int addAll(final Collection<T> coll, final T... objs) { int i = 0; for (final T e : objs) { if (coll.add(e)) { i++; } } return i; } }