Java で既存のオブジェクト ファイルにオブジェクトを追加するにはどうすればよいですか?

public class AppendingObjectOutputStream extends ObjectOutputStream {

  public AppendingObjectOutputStream(OutputStream out) throws IOException {
    super(out);
  }

  @Override
  protected void writeStreamHeader() throws IOException {
    // do not write a header, but reset:
    reset();
  }

}

FileOutputStream fos = null;
ObjectOutputStream out = null;

File file = new File(preferences.getAppDataLocation() + "history");

if (file.exists()) {
  // Append to existing file
  fos = new FileOutputStream(file, true);
  out = new AppendingObjectOutputStream(fos);
} else {
  // Create new file with header
  fos = new FileOutputStream(file);
  out = new ObjectOutputStream(fos);
}

// Append objects to the file
out.writeObject(new Stuff(stuff));
out.close();