Applet using URLConnection.setUseCaches (true) cause OutOfMemoryError

Hi all,
I had this prloblem for a couple of weeks.
We had a applet app that retrieve images and show on applet pages. On the applet page there are some image icon like print, rotation, copy ... on the sidebar, also I have two jar files including those classes and images on sever. When users access the applet page, the applet image (a document) show up immediately, but the button icon loading very slow one by one. From java console I can see one jar file which contain image icons were loaded multiple times and very slow about 8 to 10 minuts, after complete loaded, retrieve others will be fine.
I think the cache set to false cause that.
               urlConnection.setUseCaches (*false*);
               urlConnection.setDefaultUseCaches (*false*);But if I set to true:
               urlConnection.setUseCaches (*true*);
               urlConnection.setDefaultUseCaches (*true*);My understanding is that allow to loading very image into local cache. After user retrieve images (about 30 times, they clicked on a document icon to show the image) for certain times, the browser frozen and java console show a error:
com.ibm.mm.viewer.CMBDocumentEngineException: Java heap space
java.lang.OutOfMemoryError: Java heap space
I tried jre1.4.2, 1.5 and 1.6.0_02/_06/_10, didn't work!
jre1.4.1 was fine but our user will use jre1.5 or higher.
Anybody has a solution?
Many thanks!!!
Jx
Edited by: cooooooooool on Nov 25, 2008 7:19 AM

Ah, turns out I had to read the input too. Though I didn't produce much output myself in the script ;)

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If in the URLconnection I setUseCaches(true), I must to wait until...

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import java.io.*;
* A class that bundles the ChatCallback reference with a public name used
* by the client.
class ChatClient {
private ChatCallback callback;
private String publicName;
ChatClient(ChatCallback cbk, String name) {
     callback = cbk;
     publicName = name;
// returns the name.
String getName() {
     return publicName;
// returns a reference to the callback object.
ChatCallback getCallback() {
     return callback;
public class ChatServerImplementation extends UnicastRemoteObject
implements ChatServer {
// The table of clients connected to the server.
Hashtable clients;
// Tne number of current connections to the server.
private int currentConnections;
// The maximum number of connections to the server.
private int maxConnections;
// The output stream to write messages to.
PrintWriter writer;
* Create a ChatServer.
* @param maxConnections the total number if connections allowed.
public ChatServerImplementation(int maxConnections) throws RemoteException {
     clients = new Hashtable(maxConnections);
     this.maxConnections = maxConnections;
* Increment the counter keeping track of the number of connections.
synchronized boolean incrementConnections() {
     boolean ret = false;
     if (currentConnections < maxConnections) {
     currentConnections++;
     ret = true;
     return ret;
* Decrement the counter keeping track of the number of connections.
synchronized void decrementConnections() {
     if (currentConnections > 0) {
     currentConnections--;
* Register with the ChatServer, with a String that publicly identifies
* the chat client. A String that acts as a "magic cookie" is returned
* and is sent by the client on future remote method calls as a way of
* authenticating the client request.
* @param object The ChatCallback object to be used for updates.
* @param publicName The String the object would like to be known as.
* @return The actual String assigned to the object for removing, etc. or
* null if the client could not register.
public synchronized String register(ChatCallback object, String publicString) throws RemoteException {
     String assignedName = null;
     if (incrementConnections()) {
     ChatClient client = new ChatClient(object, publicString);
     assignedName = "" + client.hashCode();
     clients.put(assignedName, client);
     out("Added callback for: " + client.getName());
     return assignedName;
* Remove the client associated with the specified registration string.
* @param registeredString the string returned to the client upon registration.
public synchronized void unregister(String registeredString) throws RemoteException {
     ChatCallback cbk;
     ChatClient sender;
     if (clients.containsKey(registeredString)) {
     ChatClient c = (ChatClient)clients.remove(registeredString);
     decrementConnections();
     out("Removed callback for: " + c.getName());
     for (Enumeration e = clients.elements(); e.hasMoreElements(); ) {
          cbk = ((ChatClient)e.nextElement()).getCallback();
          cbk.addMessage("ChatServer",
                    c.getName() + " has left the building...");
     else {
     out("Illegal attempt at removing callback (" + registeredString + ")");
* Sets the logging stream.
* @param out the stream to log messages to.
protected void setLogStream(Writer out) throws RemoteException {
     writer = new PrintWriter(out);
* The client is sending new message to the server.
* @param assignedName the string returned to the client upon registration.
* @param data the chat data.
public synchronized void sendMessage(String registeredString, String message) throws RemoteException {
     ChatCallback cbk;
     ChatClient sender;
     try {
     out("Recieved from " + registeredString);
     out("Message: " + message);
     if (clients.containsKey(registeredString)) {
          sender = (ChatClient)clients.get(registeredString);
          for (Enumeration e = clients.elements(); e.hasMoreElements(); ) {
               cbk = ((ChatClient)e.nextElement()).getCallback();
               cbk.addMessage(sender.getName(), message);
     else {
          out("Client " + registeredString+ " not registered");
     catch(Exception ex){
     out("Exception thrown in newData: " + ex);
     ex.printStackTrace(writer);
     writer.flush();
* Write s string to the current logging stream.
* @param message the string to log.
protected void out(String message){
     if(writer != null){
     writer.println(message);
     writer.flush();
* Start up the Chat server.
public static void main(String args[]) throws Exception {
     try {
     // Create the security manager
     System.setSecurityManager(new RMISecurityManager());
     // Instantiate a server
     ChatServerImplementation c = new ChatServerImplementation(10);
     // Set the output stream of the server to System.out
     c.setLogStream(new OutputStreamWriter(System.out));
     // Bind the server's name in the registry
     Naming.rebind("//" + args[0] + "/ChatServer", c);
     c.out("Bound in registry.");
     catch (Exception e) {
     System.out.println("ChatServerImplementation error:" +
                    e.getMessage());
     e.printStackTrace();
Using my own machine (connected to a network), I tried to test this one out by setting mine as the server and also the client. I did the following:
1. Compile the source code.
2. Use rmic to generate the skeletons and/or stubs from the ChatCallbackImplementation and ChatServerImplementation.
3. Start the rmiregistry with no CLASSPATH
4. Start the server successfully.
5. Start the applet using the AppletViewer command.
It worked fined.
The problem is when I ran the applet using the browser, IE explorer, the dialog boxes, frame and buttons did appear. I was able to do the part of logging on. But after that, the applet seemed to have hang. No message appeared that says I'm connected (which appeared using the appletviewer). I clicked the send button. No response.
I double-checked my classpath. I did have my classpath set correctly. I'm still trying to figure out the problem. Up to now, I don't have any clue what it is.
I will appreciate much if someone can help me figure what's could have possibly been wrong ....
Thanks a lot ...

Hi Domingo,
I had a similar problem running applet/rmi with IE.
Looking in IE..view..JavaConsole error messages my applet was unable to find java.rmi.* classes.
I checked over java classes in msJVM, they're not present.
( WinZip C:\WINDOWS\JAVA\Packages\9rl3f9ft.zip and others from msVM installed )
( do not contain the java.rmi.* packages )
I have downloaded and installed the latest msJVM for IE5. ( I think its included in later versions)
@http://www.objectweb.org/rmijdbc/RJfaq.html I found ref to rmi.zip download to provide
these classes. I couldn't get the classes from the site but I managed to find a ref to IBM
site @http://alphaworks.ibm.com/aw.nsf/download/rmi which had similar download.
The download however didn't solve my problems. I was unable to install rmi.zip with
RmiPatch.exe install.
I solved this by extracting the class files from rmi.zip and installing them at C:\WINDOWS\JAVA\trustlib ( msJVM installation trusted classes lib defined in
registry HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Java VM\TrustedLibsDirectory )
This solved the problem. My rmi/applet worked.
Hope this helps you.
Chris
([email protected])

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When I add javaFX I am not able to compile my application as jfxrt.jar also has a JSObject implementation, but without the getWindow method.
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However, after compiling within NetBeans 3.6 (J2SE 1.4), it runs only when using the AppletViewer within the NetBeans. It does not execute when I shift the browser to Internet Explorer within NetBeans, or when I try to do it through a HTML file outside NetBeans.
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However, after compiling within NetBeans 3.6 (J2SE
1.4), it runs only when using the AppletViewer within
the NetBeans. It does not execute when I shift the
browser to Internet Explorer within NetBeans, or when
I try to do it through a HTML file outside NetBeans.You can enable the displaying of the Java console for the Explorer Java plug-in. This will allow you to see any exceptions happening which might be causing your problem. If no exceptions are happening, then it's likely the class path in the packages don't match where your running it from.
I noticed that this behaviour starts after creating
the .class file with NetBeans. If I create the .class
file using the javac compiler in a Solaris computer I
have access to, it executes both in the Solaris
machine (Netscape browser) and in a PC.Try building a JAR file, and running your applet from the jar in Explorer. Running from classes can cause problems if the folders they exist in don't map out the same as the packages.

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Hi,
I have an applet which is working fine under JRE 1.4, but the same applet failing to load by using JRE 1.5
Problem Description:
1. The images in the applet fails to load using JRE 1.5
2. The Username and Password text box are also failing to initialize.
Can anyone help me out in this.
Is there any code changes required ?

I wonder if you have the same problem as me... Maybe we can find a solution for us both, no need for me to open a new thread for this topic then...
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Try restoring the iPhone to factory settings. If you are having difficult restoring, put the iPhone into Recovery Mode and see if that then works:
http://support.apple.com/kb/ht1808
If not, or if a restore to factory settings does not fix the problem, then your iPhone may have a hardware problem. You can only get the iPhone serviced by Apple in Canada, so you will have to take the iPhone there or send it to someone you know in Canada who can get the iPhone serviced and send it back to you. The only option for getting service in Pakistan would be to pay some unauthorized repair shop to attempt a repair, after which Apple will no longer provide any service even in Canada.
Regards.

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JSObject documentObject = (JSObject) windowObject.getMember("document");
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documentObject.call("open",null);
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anArray1[0] ="some HTML here";
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Here is the code that I use with 1.4.0 plugin:
JSObject windowObject = JSObject.getWindow(this);
JSObject documentObject = (JSObject) windowObject.getMember("document");
String anArray1[] = {null};
anArray1[0] ="some HTML here";
documentObject.call("write", anArray1);
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Hi,
I am doing this in my applet to replace the page containing the applet with the new content. I tested that extensively with Netscape 4.7 and IE 5.5+. Definitely works if you are using Java Plug-In 1.3.1_02. Does not work well in Netscape 6.2.
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