Swing Worker wont start copy files

Question

I want to create a swing worker that copies file and shows the progress in a progress bar. SIt all works fine except the process() function although I copied paste the code I found in a blog - I don't remember the link to show you, I get compilation errors. Here is my code:

    class Copy extends SwingWorker<Void, Void>
           {
             File src,dest;
             InputStream in;
             OutputStream out;
             JProgressBar bar;
              public Copy(File source,File dst)
              {
                 src=source;
                 dest=dst;
                 //bar=Br;
                 progressBar.setValue(0);
              }

              public Copy(MouseAdapter mouseAdapter) {
                // TODO Auto-generated constructor stub
            }

            protected Void doInBackground() throws Exception
              {
                System.out.print("Started\n");
                InputStream input = null;
                OutputStream output = null;
                try {
                    input = new FileInputStream(src);
                    output = new FileOutputStream(dest);
                    byte[] buf = new byte[1024];
                    int bytesRead;
                    while ((bytesRead = input.read(buf)) > 0) {
                        output.write(buf, 0, bytesRead);
                    }
                } finally {
                    input.close();
                    output.close();
                }
                progressBar.setVisible(true);
                return null;
              }


    //Here I get the error:
    @Override //Description Resource    Path    Location    Type
    //The method process() of type Main.Copy must override or implement a supertype method

                  protected Void process()
                  {
                      long expectedBytes = src.length(); // This is the numbe

r of bytes we expected to copy..
                  byte[] buffer = new byte[1024];
                  int length;
                  long totalBytesCopied = 0; // This will track the total number of bytes we've copied

                  try {
                    while ((length = in.read(buffer)) > 0){
                          out.write(buffer, 0, length);
                          totalBytesCopied += length;
                          int progress = (int)Math.round(((double)totalBytesCopied / (double)expectedBytes) * 100);
                          System.out.print(progress);
                          progressBar.setValue(progress);
                      }
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                //  return progress;
              }

              protected void done()
              {
                  System.out.print("Complete\n");
              }

           }   
        }

I cannot understand what I am doing wrong so a little help would be appreciated. Also what is the difference between Void

e.g protected Void doInBackground()

and void

e.g protected void done()

I am currently working in Eclipse and these two have different colours at the editor so there's a difference between them.