Cannot see zipped files in Windows Explorer

Question

I used the code below to create a zip file. When I use Winzip to open a zip file named test.zip, I can see all the files (a.txt, b.class, etc.) that have been zipped. But, when I double-click on the test.zip in Windows Explorer (Windows XP Professional), I cannot see any of the zipped files.
Can someone give me some pointers?
import java.util.*;
import java.util.zip.*;
import java.io.*;
public class CreateZip
     public CreateZip()
     public void createZipFile(String[] all_array, String zipfilename)
          FileOutputStream pout; // declare a file output object
PrintStream p;
          String file_path = "D:\\Docs\\FedPlanner\\";
try
pout = new FileOutputStream(file_path + "FedPlanner_Zip_log.txt");
p = new PrintStream( pout );
               for (int i = 0; i < all_array.length; i++)
                    System.out.println("all_array = " + all_array);
                    p.println (all_array[i]);
p.close();
catch (Exception e)
System.err.println ("Error writing to file");
          byte[] buf = new byte[1024];
          try
               String outFilename = file_path + zipfilename;
          ZipOutputStream out = new ZipOutputStream(new FileOutputStream(outFilename));
               for (int i=0; i< all_array.length; i++) //
               FileInputStream in = new FileInputStream(file_path + all_array[i]);//filenames
               out.putNextEntry(new ZipEntry(file_path +all_array[i]));//filenames
               int len;
               while ((len = in.read(buf)) > 0)
               out.write(buf, 0, len);
               out.closeEntry();
               in.close();          
          out.close();
          catch (IOException e)
               e.printStackTrace();
     public static void main(String args[])
          for(int i=0; i < all_array.length; i++)
               System.out.println("x = " + all_array[i]);
          CreateZip create = new CreateZip();
          create.createZipFile(all_array);

Answer 1

I have never created a zip file using Java . But from what i know about Winzip and Window Explorer, here's my takes on it:
1. Winzip works with severals different compression algorithm 9including their own)
2. Winzip has the ability to display the content of the zip file (if the zip file happens to be one of the compression algorithm they supported....otherwise, it's highly unlikely, winzip can even open the file)
3. Window Explorer does not call Winzip to display the content of Winzip file. rather, Window Explorer has its own utility to look into the Winzip for files and display them. Note: they probably only do this for the popular compression algorith (such as Winzip .zip, probably .tar...but highly doubtful of the one that Java use to make a zip file).
So..it's probably Window Explorer does not supports display that compression algorithm (the one Java use) for a Winzip file.
Example...you created a new format for an image call .mypics
Window Explorer can display a thumb nail for .bmp, .jpeg, and quite a few other
You created an application to display the image. Now..in Window Explorer, when you click on the icon, the thumbnail of the pic is not display...this is because Window Explorer does not have a util to do thumbnail for that format.