Here you can find the source of isNotEmpty(Collection> collection)
public static boolean isNotEmpty(Collection<?> collection)
//package com.java2s; import java.util.Collection; import java.util.Map; public class Main { public static boolean isNotEmpty(Map<?, ?> map) { return (map != null) && (map.size() > 0); }//from w w w .j a v a 2 s. com public static boolean isNotEmpty(Collection<?> collection) { return (collection != null) && (collection.size() > 0); } }