FULL PRODUCT VERSION :

Java 1.6.0 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode

ADDITIONAL OS VERSION INFORMATION :
Windows XP

A DESCRIPTION OF THE PROBLEM :
When calling File.isDirectory using a UNC pathname performance is extremely slow.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a File object using a unc pathname.
Call File.list() to get a list of filenames in the directory.
For each filename in the list, create a new
File("unc pathname", filename")
and call isDirectory().
Performance slows to a point it appears application is hung.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.*;
import javax.swing.*;

public class isdir extends JFrame
{
    public isdir()
    {
        init();
    }

    private void init()
    {
        File test;
// substitue a UNC pathname
        File dir = new File( "\\\\mathworks\\public");
        boolean loop = true;
        String[] filelist = null;
filelist = dir.list(); // get files

       int totalNumFiles = filelist.length;
   
        for (int i = 0; i < totalNumFiles; i++)
        {
// works fine with a mapped drive
            // test = new File("p:", filelist[i]);
// substitue a unc pathname
               test = new File("\\\\mathworks\\public", filelist[i]);
               if (test.isDirectory())
                 System.out.println(test.getName() + " is Directory.");
             else
                 System.out.println(test.getName() + " is not a Directory.");
        }

    }

    public static void main(String[] args)
    {
        isdir frame = new isdir();
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Instead of using a UNC pathname, map a drive letter.