Content type problem for 'does not appear to be a proper arcive'

Question

Hi all,
The following code will create a ZipOutputStream using ByteArrayOutputStream (not FileOutputStream) and attach the outputstream to a MIME multipart email using ByteArrayDataSource (so the file never exists physically).
It works and sends the email but the zip 'does not appear to be a valid archive' even though it looks about the right size. If I do the same and use FileOutputStream to create a physical file it works OK. I think it is an issue with the content type, or maybe this just isn't possible!
I have tried:
byteArray.toByteArray(),
byteArray.toString().getBytes() and application/zip & application/unknown.
Can anyone help or suggest an alternative way to create a 'in-memory' zip file that can then be emailed?
Many thanks
    // Specify files to be zipped
                                                             String[] filesToZip = new String[3];
                                                             filesToZip[0] = "C:\\Program Files\\NetBeans3.6\\firstfile.txt";
                                                             filesToZip[1] = "C:\\Program Files\\NetBeans3.6\\secondfile.txt";
                                                             filesToZip[2] = "C:\\Program Files\\NetBeans3.6\\thirdfile.txt";
                                                             byte[] buffer = new byte[18024];
                                                             // Specify zip file name
                                                              String zipFileName= eq_rt.getReportName() + ".zip";
                                                             try {
                                                               // Create ZipOutputStream to store the FileOutputStream
                                                               //ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFileName));
                                                               ByteArrayOutputStream byteArray = new ByteArrayOutputStream();                                                             
                                                               ZipOutputStream out = new ZipOutputStream(byteArray);                                                              
                                                               // Set the compression ratio
                                                               out.setLevel(Deflater.DEFAULT_COMPRESSION);
                                                               // iterate through the array of files, adding each to the zip file
                                                               for (int a = 0; a < filesToZip.length; a++) {
                                                                 System.out.println(a);
//                                                                 // Associate a file input stream for the current file
                                                                 FileInputStream in = new FileInputStream(filesToZip[a]);
                                                                 // This ROCKS as it is passing a array into the text file .getBytes() seems
                                                                 // to be the KEY in getting ByteArrayInputStream to WORK
                                                                 String strSocketInput = "TAIWAN";
                                                                 ByteArrayInputStream baIn = new ByteArrayInputStream(strSocketInput.getBytes());
                                                                 //ByteArrayInputStream baIn = new ByteArrayInputStream( getAttachementNoFormat(eq_rt.getStoredProc() ) );                                                               
                                                                 // Add ZIP entry to output stream.
                                                                 out.putNextEntry(new ZipEntry(filesToZip[a]));
                                                                 // Transfer bytes from the current file to the ZIP file
                                                                 int len;
                                                                 while ((len = baIn.read(buffer)) > 0)
                                                                 out.write(buffer, 0, len);
                                                                 // Close the current entry
                                                                 out.closeEntry();
                                                                 // Close the current file input stream
                                                                 baIn.close();                                                   
                                                              // DataSource sourcezip = new FileDataSource(zipFileName);
                                                               //DataSource sourcezip = new ByteArrayDataSource(byteArray.toByteArray(), zipFileName, "application/octet-stream");   
                                                                DataSource sourcezip = new ByteArrayDataSource(byteArray.toByteArray(), zipFileName, "application/octet-stream" );
                                                               // Create a new MIME bodypart
                                                               BodyPart attachment = new MimeBodyPart();
                                                               attachment.setDataHandler(new DataHandler(sourcezip));
                                                               attachment.setFileName(zipFileName);                       
                                                               /* attach the attachemnts to the mail */
                                                               multipart.addBodyPart(attachment);                                                                
                                                               // Close the ZipOutPutStream
                                                               out.close(); 

Answer 1

Many thanks Dr Clap. Moving the Closing the ZipOutputStream before I attached it to the email solved my problem.
                                      /* Close the ZipOutPutStream (very important to close the zip before you attach it to the email) Thanks DrClap */
                                                                out.close();                                                    
                                                                /* Create a datasource for email attachment */
                                                                // DataSource sourcezip = new FileDataSource(zipFileName);
                                                                DataSource sourcezip = new ByteArrayDataSource(byteArray.toByteArray(), zipFileName, "application/zip" );
                                                                /* Create a new MIME bodypart */
                                                                BodyPart attachment = new MimeBodyPart();
                                                                attachment.setDataHandler(new DataHandler(sourcezip));
                                                                attachment.setFileName(zipFileName);                       
                                                                /* attach the attachemnts to the mail */
                                                                multipart.addBodyPart(attachment);