Here you can find the source of isNull(Collection> collection)
public static boolean isNull(Collection<?> collection)
//package com.java2s; //License from project: Apache License import java.util.Collection; public class Main { public static boolean isNull(Collection<?> collection) { if (collection == null || collection.isEmpty()) { return true; }/*from w w w .j a va 2 s.co m*/ return false; } }