Posting to a servlet from a class in a jar on the server

Question

I'm trying to modify a 3rd party applet that displays documents pulled from a database to post back to the server whenever the user pages up/down into a new document. The primary functionality of the applet is in place and working, the only change I am trying to make is to get the applet to post back to the server when the document being viewed changes so that we can keep track of documents open on the server side.
The document viewer in the applet does have documented, though limited, ways to modify its functionality through properties files. I've added page up/down buttons to the correct properties file and specified button implementation classes as is dictated by their documentation. However, the problem I've run into is that since these page up/down classes are supposed to be placed in a jar file on the server and sent to the applet via the ARCHIVE parameter of the APPLET tag; these classes can not actually submit a post request back to the servlet.
Since these classes exist outside of the world of the web app and applet, they don't have access to any of the connection, session, or cookie info in order to have an address to post back to, much less hold the correct session during the post. I tried hard-coding a URL to send the post request to for the sake of testing, but I'm still not seeing the post request being sent to the servlet. Here is the code I used to post the request, just in case it's a stupid mistake on my part.
URL localURL = new URL("http://localhost:8080/appDir/ServletName");
                localURLConnection = localURL.openConnection();
                localURLConnection.setRequestProperty("method", "POST");
                localURLConnection.setDoOutput(true);
                Properties paramProperties = new Properties();
                paramProperties.put("command", "nextDocument");
                OutputStream localOutputStream = paramURLConnection.getOutputStream();
                ObjectOutputStream localObjectOutputStream = new ObjectOutputStream(localOutputStream);
                localObjectOutputStream.writeObject(paramProperties);
                localObjectOutputStream.flush();
                localObjectOutputStream.close();While searching to find out why this code isn't posting to my servlet, I've been wondering about the viability of this approach as a whole as well. Ideally if I wanted to add a post request to an event generated by the applet, then I would want to modify the applet. But since the applet is in a 3rd party jar file, I've been trying to do things their way. However, assuming I could get the page up/down action classes to post correctly, wouldn't I need some way of preserving the session that this action came from so that the right user's applet would be updated with the right document? The first thought that comes to mind on this involves writing out session/cookie data to temporary files on the server, but this sounds very ugly and insecure; plus I'd have to worry about making sure the files were uniquely named and that this unique name could be used in the page up/down classes. Is there a better way that I could be doing it?
I apologize for the long winded explanation, but if anyone has any thoughts on either why my post request isn't going through or on the absurdity of my solution (and hopefully an alternate idea I could try), I'd be very appreciative.
Thanks in advance.

Answer 1

Well, when I've done URL connections from an applet session and cookies seem to have sorted themselves out. I'm not sure how, but there seems to be some functionality for it in the URLConnection class.
I haven't tried setting the method like this, I always cast to HttpURLConnection and call setMethod to select POST. Your way might be right as well though.
Have you checked the server access logs?
It may be that your URL is rejected by the security manager for not having the same form of the hostname as the original applet retrieval.
You should be able to get a domain name and port from the "code source" of your code, which will reference the online jar it comes from. You can generally get at this as getClass().getProtectionDomain().getCodeSource().getLocation(), or less elegantly by requesting the current class file as a resource.