Here you can find the source of isNullOrEmpty(List list)
public static boolean isNullOrEmpty(List list)
//package com.java2s; //License from project: Apache License import java.util.List; import java.util.Set; public class Main { public static boolean isNullOrEmpty(String s) { return s == null || s.trim().isEmpty(); }//from w ww . j a v a 2 s . c o m public static boolean isNullOrEmpty(List list) { return list == null || list.isEmpty(); } public static boolean isNullOrEmpty(Set set) { return set == null || set.isEmpty(); } }