Cannot extract Zip file with Winzip after zipping with java.util.zip

Question

Hi all,
I write a class for zip and unzip the text files together which can be zip and unzip successfully with Java platform. However, I cannot extract the zip file with Winzip or even WinRAR after zipping with Java platform.
Please help to comment, thanks~
Below is the code:
=====================================================================
package myapp.util;
import java.io.* ;
import java.util.TreeMap ;
import java.util.zip.* ;
import myapp.exception.UserException ;
public class CompressionUtil {
  public CompressionUtil() {
    super() ;
  public void createZip(String zipName, String fileName)
      throws ZipException, FileNotFoundException, IOException, UserException {
    FileOutputStream fos = null ;
    BufferedOutputStream bos = null ;
    ZipOutputStream zos = null ;
    File file = null ;
    try {
      file = new File(zipName) ; //new zip file
      if (file.isDirectory()) //check if it is a directory
     throw new UserException("Invalid zip file ["+zipName+"]") ;
      if (file.exists() && !file.canWrite()) //check if it is readonly
     throw new UserException("Zip file is ReadOnly ["+zipName+"]") ;
      if (file.exists()) //overwrite the existing file
     file.delete();
      file.createNewFile();
      //instantiate the ZipOutputStream
      fos = new FileOutputStream(file) ;
      bos = new BufferedOutputStream(fos) ;
      zos = new ZipOutputStream(bos) ;
      this.writeZipFileEntry(zos, fileName); //call to write the file into the zip
      zos.finish() ;
    catch (ZipException ze) {
      throw ze ;
    catch (FileNotFoundException fnfe) {
      throw fnfe ;
    catch (IOException ioe) {
      throw ioe ;
    catch (UserException ue) {
      throw ue ;
    finally {
      //close all the stream and file
      if (fos != null)
     fos.close() ;
      if (bos != null)
     bos.close();
      if (zos != null)
     zos.close();
      if (file != null)
     file = null ;
    }//end of try-catch-finally
  private void writeZipFileEntry(ZipOutputStream zos, String fileName)
      throws ZipException, FileNotFoundException, IOException, UserException {
    BufferedInputStream bis = null ;
    File file = null ;
    ZipEntry zentry = null ;
    byte[] bArray = null ;
    try {
      file = new File(fileName) ; //instantiate the file
      if (!file.exists()) //check if the file is not exist
     throw new UserException("No such file ["+fileName+"]") ;
      if (file.isDirectory()) //check if the file is a directory
     throw new UserException("Invalid file ["+fileName+"]") ;
      //instantiate the BufferedInputStream
      bis = new BufferedInputStream(new FileInputStream(file)) ;
      //Get the content of the file and put into the byte[]
      int size = (int) file.length();
      if (size == -1)
     throw new UserException("Cannot determine the file size [" +fileName + "]");
      bArray = new byte[(int) size];
      int rb = 0;
      int chunk = 0;
      while (((int) size - rb) > 0) {
     chunk = bis.read(bArray, rb, (int) size - rb);
     if (chunk == -1)
       break;
     rb += chunk;
      }//end of while (((int)size - rb) > 0)
      //instantiate the CRC32
      CRC32 crc = new CRC32() ;
      crc.update(bArray, 0, size);
      //instantiate the ZipEntry
      zentry = new ZipEntry(fileName) ;
      zentry.setMethod(ZipEntry.STORED) ;
      zentry.setSize(size);
      zentry.setCrc(crc.getValue());
      //write all the info to the ZipOutputStream
      zos.putNextEntry(zentry);
      zos.write(bArray, 0, size);
      zos.closeEntry();
    catch (ZipException ze) {
      throw ze ;
    catch (FileNotFoundException fnfe) {
      throw fnfe ;
    catch (IOException ioe) {
      throw ioe ;
    catch (UserException ue) {
      throw ue ;
    finally {
      //close all the stream and file
      if (bis != null)
     bis.close();
      if (file != null)
     file = null ;
    }//end of try-catch-finally
}

Answer 1

Tried~
The problem is still here~ >___<
Anyway, thanks for information sharing~
The message is:
Cannot open file: it does not appear to be a valid archive.
If you downloaded this file, try downloading the file again.
The problem may be here:
if (fos != null)
fos.close() ;
if (bos != null)
bos.close();
if (zos != null)
zos.close();
if (file != null)
file = null ;
The fos is closed before bos so the last buffer is not
saved.
zos.close() is enough.