Continuously send data to applet through servlet

Question

Hi,
I'm trying to write a servlet that, once activated, will continuously send data back to a thread in the client. My problem is that the data isn't actually sent until the stream is closed. I'm hoping someone can point me in the right direction:
Servlet code:
public class testStream extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
int[] somedata = new int [1];
somedata [0] = 1000;
String contentType =
"application/x-java-serialized-object";
response.setContentType(contentType);
ObjectOutputStream out =
new ObjectOutputStream(response.getOutputStream());
while (true) {
try {
out.writeObject(somedata );
System.out.println("Sent " + somedata [0]);
somedata [0]++;
} catch(Exception ie) {}
out.flush();
Thread.yield();
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
Applet side code:
* <P>
* Taken from Core Servlets and JavaServer Pages
* from Prentice Hall and Sun Microsystems Press,
* http://www.coreservlets.com/.
* &copy; 2000 Marty Hall; may be freely used or adapted.
public class testStream implements Runnable {
private boolean isDone = false;
private URL dataURL;
public testStream(String urlSuffix, URL currentPage) {
try {
// Only the URL suffix need be supplied, since
// the rest of the URL is derived from the current page.
String protocol = currentPage.getProtocol();
String host = currentPage.getHost();
int port = currentPage.getPort();
dataURL = new URL(protocol, host, port, urlSuffix);
Thread imageRetriever = new Thread(this);
imageRetriever.start();
} catch(MalformedURLException mfe) {
System.err.println("Bad URL");
isDone = true;
public void run() {
try {
retrieveImage();
} catch(IOException ioe) {
isDone = true; // will never get hit
public boolean isDone() {  // meaningless now with infinite loop
return(isDone);
private void retrieveImage() throws IOException {
URLConnection connection = dataURL.openConnection();
connection.setUseCaches(false);
connection.setDoInput(true);
connection.setDefaultUseCaches (false);
connection.setRequestProperty("Content-Type", "application/x-java-serialized-object");
ObjectInputStream in = null;
try {
in = new ObjectInputStream(connection.getInputStream());
} catch (Exception pe) { System.err.println(pe); }
while (true) {
// loop forever requesting data
try {
// The return type of readObject is Object, so
// I need a typecast to the actual type.
int[] someData = (int[]) in.readObject();
System.err.println(someData[0]);
} catch(ClassNotFoundException cnfe) {
System.err.println("received NULL");
Thread.yield();

Answer 1

The original example was based on HTTP. I suppose yours is too. The HTTP protocol is for sending and receiving packets of finite length, and that is not your requirement. So don't use HTTP. Probably socket communications would be your best bet.