Here you can find the source of isEmpty(Collection
public static <T> boolean isEmpty(Collection<T> items)
//package com.java2s; /******************************************************************************* * Copyright (C) 2014 The Calrissian 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.//from www .ja v a 2 s . com *******************************************************************************/ import java.util.Collection; public class Main { public static <T> boolean isEmpty(T[] items) { return items == null || items.length == 0; } public static <T> boolean isEmpty(Collection<T> items) { return items == null || items.isEmpty(); } public static boolean isEmpty(String value) { return value == null || value.isEmpty(); } }