ObjectStreams

Question

Scenario: I have a Tomcat servlet engine running on a server.
Tomcat is connected to a MySQL database.
I have written an applet in Java which polls every 5 seconds (URLConnection)
to a servlet. The servlet replies whether there are updates available. When there are
updates available they get transmitted to the client. Think of thousands of objects that get transmitted to the client.
The communication process all runs with (zipped) ObjectOutputStream and ObjectInputStream.
Problem: The transfer speed is roughly in the beginning 1MB/s but the longer the client is connected and the more objects are streamed, the speed
drops down to 400 KB/s. This happends out of the blue. Also why is 1MB/s a limit? Why not 10MB or 50MB?
My question: Can someone summarize what steps Java does hardware-wise when using ObjectOutputStream and ObjectInputStream?
I've read the API and know the technique behind object serialization and how Java handles this all.
I am interested in knowing where the bottleneck lies. When I look at my CPU, it is barely in use. (10%).
When I look at RAM, I notice -nothing- is swapping. Disk I/O isn't extraordinairy high as well..
Finally as a sidenote, caching of ObjectStreams is unshared. Meaning objects arent cached.

Answer 1

Im guessing you're aiming at HttpURLConnection.
I'm not using that. Also not sure if that was an advise to start using it...
I've decided to add some code to give an impression how it works.
    private URLConnection CreateConnection(URL urlServlet) throws IOException
        URLConnection connection = urlServlet.openConnection();
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setUseCaches(false);
        connection.setRequestProperty("Content-Type", "application/x-java-serialized-object");
        return connection;
public static Poll doPollingRequest(URLConnection urlCon, Poll pollObj) throws ClassNotFoundException
        OutputStream outstream = null;
        Poll replyPoll = null;
        try
            outstream = urlCon.getOutputStream();
            GZIPOutputStream gout = new GZIPOutputStream(outstream);
            ObjectOutputStream oos = new ObjectOutputStream(gout);
            oos.writeObject(pollObj);
            oos.flush();
            oos.close();
            InputStream instr = urlCon.getInputStream();
            GZIPInputStream gin = new GZIPInputStream(instr);
            ObjectInputStream inputFromServlet = new ObjectInputStream(gin);
            replyPoll = (Poll) inputFromServlet.readObject();
            inputFromServlet.close();
            gin.close();
            instr.close();
        } catch (IOException ex)
            Logger.getLogger(Polling.class.getName()).log(Level.SEVERE, null, ex);
        } finally
            try
                outstream.close();
            } catch (IOException ex)
                Logger.getLogger(Polling.class.getName()).log(Level.SEVERE, null, ex);
        return replyPoll;
    }The doPollingRequest works with a "Poll" object. There are all kinds of objects that get streamed to update or alter the client after the client requests them.