Here you can find the source of getFirst(Collection
public static <T> T getFirst(Collection<T> l)
//package com.java2s; /*//from w w w. j a v a 2 s .co m * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright 2011 OpenConcerto, by ILM Informatique. All rights reserved. * * The contents of this file are subject to the terms of the GNU General Public License Version 3 * only ("GPL"). You may not use this file except in compliance with the License. You can obtain a * copy of the License at http://www.gnu.org/licenses/gpl-3.0.html 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. */ import java.util.Collection; import java.util.List; public class Main { public static <T> T getFirst(Collection<T> l) { return l.size() > 0 ? l.iterator().next() : null; } /** * Return the first item of <code>l</code> if it isn't empty, otherwise <code>null</code>. * * @param <T> type of list. * @param l the list. * @return the first item of <code>l</code> or <code>null</code>. */ public static <T> T getFirst(List<T> l) { return getNoExn(l, 0); } /** * Return the item no <code>index</code> of <code>l</code> if it exists, otherwise * <code>null</code>. * * @param <T> type of list. * @param l the list. * @param index the wanted index. * @return the corresponding item of <code>l</code> or <code>null</code>. */ public static <T> T getNoExn(List<T> l, int index) { return index >= 0 && index < l.size() ? l.get(index) : null; } }