求救String数组的排序有关问题

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;public class Temp{    public static void main(String args[])    {        String[] str = new String[]{"19.mp3","1.mp3","2.mp3"};                 for(Object s: sort(str))        {            System.out.println(s);        }    }        public static String[] sort(String[] strs)    {        String[] ret = new String[strs.length];        List<String> list = new ArrayList<String>();                for(String str: strs)        {            list.add(str);        }                Collections.sort(list, new CustomComparator());                for(int i = 0; i < list.size(); i++)        {            ret[i] = list.get(i);        }                return ret;    }}class CustomComparator implements Comparator<String>{    public int compare(String str1, String str2)    {        int name1 = Integer.parseInt(str1.substring(0, str1.indexOf(".")));        int name2 = Integer.parseInt(str2.substring(0, str2.indexOf(".")));        return name1 - name2;    }}