Can You Append to Existing ObjectOutputStreams in Java?

Appending to Existing Object Streams

The question arises whether it is feasible to append to an ObjectOutputStream. An attempt to append a list of objects intermittently fails while reading, resulting in a java.io.StreamCorruptedException.

The typical usage involves:

FileOutputStream fos = new FileOutputStream
           (preferences.getAppDataLocation() + "history" , true);
ObjectOutputStream out = new ObjectOutputStream(fos);

out.writeObject( new Stuff(stuff) );
out.close();

Subsequently, while reading:

FileInputStream fis = new FileInputStream
        ( preferences.getAppDataLocation() + "history");
ObjectInputStream in = new ObjectInputStream(fis);    

try{
    while(true)
        history.add((Stuff) in.readObject());
}catch( Exception e ) { 
    System.out.println( e.toString() );
}

Subclassing ObjectOutputStream and overriding the writeStreamHeader method provides the solution:

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:
    // this line added after another question
    // showed a problem with the original
    reset();
  }

}

Instantiate an appendable stream if the history file exists (append without a header) or an original stream if it doesn't exist (create with a header).

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