Here you can find the source of getSingle(Collection
public static <T> T getSingle(Collection<T> configs)
//package com.java2s; /******************************************************************************* * Copyright (c) 2015 Pivotal, Inc.//from w w w. j a va 2 s . co m * 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: * Pivotal, Inc. - initial API and implementation *******************************************************************************/ import java.util.Collection; public class Main { public static <T> T getSingle(Collection<T> configs) { if (configs.size() == 1) { for (T t : configs) { return t; } } return null; } }