Here you can find the source of getSingleElementOrNull(Iterable
public static <T> T getSingleElementOrNull(Iterable<T> coll)
//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://from www . j av a 2 s .c o m * Bruno Medeiros - initial implementation *******************************************************************************/ import java.util.Iterator; public class Main { /** * @return the first element of given coll, if collection is non-null and non-empty. Otherwise null. */ public static <T> T getSingleElementOrNull(Iterable<T> coll) { if (coll == null) return null; Iterator<T> iterator = coll.iterator(); T firstElement = iterator.next(); return iterator.hasNext() ? null : firstElement; } }