我这个upload错哪了

我这个upload哪里错了？
怎摸我的/message（路径绝对正确）目录存在，但一运行就抛这个异常的？
Exception:

  java.lang.ArrayIndexOutOfBoundsException:   0
  newsf.UploadTest.doPost(UploadTest.java:31)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note   The   full   stack   trace   of   the   root   cause   is   available   in   the   Apache   Tomcat/5.0.27


我的upload的那个servlet是这样写的：

  package   newsf;

import   javax.servlet.*;
import   javax.servlet.http.*;
import   java.io.*;
import   java.util.*;
import   com.upload.beans.Upload;

public   class   UploadTest
        extends   HttpServlet   {
    private   static   final   String   CONTENT_TYPE   =   "text/html;   charset=GB18030 ";
    private   Random   rnd=new   Random();

    //Initialize   global   variables
    public   void   init()   throws   ServletException   {
    }

    //Process   the   HTTP   Post   request
    public   void   doPost(HttpServletRequest   request,   HttpServletResponse   response)   throws
            ServletException,   IOException   {
        String   path=getServletContext().getRealPath( "message ");
        String   name=null;

        Upload   up=new   Upload();
        up.init(request);
        //up.setMaxFileSize(10   *   1024   *   1024);
        up.setSaveDir(path);
        up.setTagFileName(getRandName());

        up.uploadFile();
        name=up.getFileName()[0];
        up.getParameter( "title ");
        response.sendRedirect( "message/ "+name);
    }

    private   String   getRandName(){
        return   String.valueOf(rnd.nextLong());
    }
    //Clean   up   resources
    public   void   destroy()   {
    }
}


------解决方案--------------------
common-io.jar导入了吗。。。。。。。。
------解决方案--------------------
name=up.getFileName()[0];
------解决方案--------------------
ArrayIndexOutOfBoundsException 明显的是数组越界了