Here you can find the source of isEmpty(List> list, String message)
public static void isEmpty(List<?> list, String message)
//package com.java2s; //License from project: Apache License import java.util.List; public class Main { public static void isEmpty(List<?> list, String message) { if (list == null || list.isEmpty()) { return; }/*from ww w . j a v a 2 s . c o m*/ throw new IllegalArgumentException(message); } }