Java tutorial
//package com.java2s; /******************************************************************************* * Copyright (c) 2007 DSource.org and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Bruno Medeiros - initial implementation *******************************************************************************/ import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.List; public class Main { /** @return a new {@link ArrayList} from given collection * (a null collection is considered as if it's an empty one). */ public static <E> ArrayList<E> createArrayList(Collection<? extends E> collection) { return new ArrayList<E>(collection == null ? Collections.EMPTY_LIST : collection); } /** @return a new {@link ArrayList} from given array (a null array is considered like it's an empty one). */ @SafeVarargs public static <E> ArrayList<E> createArrayList(E... array) { ArrayList<E> newCollection = new ArrayList<E>(); if (array != null) { Collections.addAll(newCollection, array); } return newCollection; } public static <E, T extends List<? super E>> T addAll(T coll, Collection<E> other) { coll.addAll(other); return coll; } }