Java tutorial
//package com.java2s; import java.util.Collection; import java.util.List; import java.util.Map; public class Main { public static String[] toStringArray(List<String> list) { if (isEmpty(list)) { return new String[0]; } String[] array = new String[list.size()]; return list.toArray(array); } public static boolean isEmpty(Collection<?> c) { return c == null || c.isEmpty(); } public static boolean isEmpty(Map<?, ?> map) { return map == null || map.isEmpty(); } @SafeVarargs public static <T> boolean isEmpty(T... array) { return array == null || array.length == 0; } }