As sproingie said, considering that you want to implement this in a LAN environment it doesn't matter much which option you choose.
What you might think about though is that with the first method (polling every x seconds) you have a chance of the client having the wrong number for quite some time (bit less than x seconds in the worst case). Using the second method you have the new number on the client always only short time after the server has the new number (since it's the server that can then complete request whenever he wants - e.g. when he has a new number to send)

Sry for late answer. Processing input form a server without a request is something that is not yet widely supported by current browsers. You could do something like a heartbeat-system where you let the client send a request every 30 seconds or so to the server that answers the number you would like to change.
It is (or has been) however afaik disregarded as bad practice because of the additional traffic that such requests cause. In your case though that would not matter because it is only LAN and only one single number that gets updated.

Another approach is a very long Request that stays open until a certain "Event" causes the Server to respond. After that the Client immediately sends another request, again waiting for the server to respond.

Wikipedia-Article

Also google spits out tons of information on that subject. Including some ready-to-use frameworks that use those approaches:

push ajax

Hope it helps 

Not much different than you would do on the internet. The Server has to run some kind of Web-Server that can accept and process requests that you send to it. So instead of sending the AJAX Request to a certain homepage you prepare your Webpage (or whatever you want) to send it to the IP-Adress of that Server.

Is there something specific you want to know about?

Edit: Re-read your post. Do you mean to send an AJAX response to the client without a foregoing request of that client?

I'm not sure that i fully understand what you are trying to accomplish but you could do

You could then read the Class Property as normal Text-Value (Maybe use the real Class name -> could use Reflection to instanciate) and the entries as Map-Object, where you can then iterate over the Content and fill your ArrayMap Object with the Keys and Values.

Create a SQL User.
GRANT that User INSERT on your Highscore-Table. Maybe UPDATE if you just want one entry per user.

Use a System like Minecraft -> Username and Password for Game needed (Maybe only at the point where the Highscore gets sent).

When the Highscore is to be submitted -> send score along with username and pw (and other data to be stored) To a php script. If valid credentials -> store in Highscore DB, if not -> give client signal to explode.

SQL Injections and cheating on Client-side are things that have to be considered always and everywhere.

PS.: SQL Injections can be dealt with when you escape characters per default and perform validity checks on the values. If a score consists of anything else than numbers its rubbish for example (depends on your game of course). But how you could deal with cheating -> no idea

@Riven: I did not want to state that GridBagLayout is the optimal solution for Eyesackerys Problem. Only that a complex LayoutManager isn't necessarily hard to use.

I fail to see the Problem everybody is having with GridBagLayout.

Took me 3 minutes to get this running and it seems not that far from what you want to do.

http://pastebin.java-gaming.org/8eeae3e8c29

Maybe if you explained your intended use for south- and westPanel a bit more i could help you even further.

Care to take more than one Person on Board? I'm in quite exactly the same Situation like Alessandro. I start a lot of projects that i get to an (almost) playable state but then i lose interest. And also Freetime is something i don't have plenty of, but i'm willing to invest it in game development.

Timezone might be a problem though. So let me know if you'd like to give it a try. 

So i possibly have to change my mind about w3schools after all. 
Reading the Posts and the information bits around the code on w3schools proofes to be a bit frustrating.

Still i'm missing a how to at the bottom of the majority of the how not to sections. They do describe whats wrong. But not how to make it right. Some code-snippets would sometimes be nice.

Just saw that i suggested a German Help-Site in an english Forum  *facepalm*. Sorry for that. Force of habit.


It did (and still does) work for me. I think if you approach the tutorials on w3schools with a certain amount of skepticism and caution it may work quite well for some fundamental basics. As i mentioned i never really read something mindblowing wrong.

@ra4king Are we talking about false practices here or really about errors?
@Riven same question. How would you define that "significant amount of false information"?

I second that suggestion. Choose a Design you like once and forget about it. All you have to do from there is to pump out Sites/Content. Might be just the thing for you. 

I was not aware that seemingly w3schools presents you with wrong information.
I for my part never stumbled upon something error-prone and liked the Feature where you can tamper around with the code directly online without much hassle.
But i also have to admit that i never read the explaining paragraphs around the bits of code since that is all i need (use it more like a quick reference than to learn).

Might keep my eyes open for aforementioned wrong informations the next time i stop by at w3schools.

Since i have developed some Sites i might be able to help you here and there.

Should questions rise concerning JavaScript, HTML, CSS or a Combination of all three i will do my best to answer them.

Some references:
http://www.w3schools.com/
http://de.selfhtml.org/

These are my choice when it comes to looking up how to use "this" HTML-Element for "that" purpose, the Syntax of a Function in JavaScript or debugging both for Errors/Mistakes.

Sometimes you will find a "best practice" or "how NOT to...". Often spared me countless Hours of Searching and Optimizing.

And a little extra: http://www.csszengarden.com/ - what can be done with the same source and some CSS 

Thanks for the warm welcome. I had to write something sometime. I got so much Information for my own Projects just being passive and reading the Topics of the Forum. First thing wenn i start up my Machine is reading news and new posts in Topics I'm interested in. Kinda keeps me informed what the latest best practices or librarys are. Just to keep up with changes that occur every day (or so it seems).

So i figured i'd start to give something back, hoping that somebody could use parts of my rambling to solve his/her problems or questions like i do quite a few times.  

Just looked at a few of the Examples from the URL you posted.

A lot of these Designs can be achieved with a Combination of CSS-structured HTML and a bit of JavaScript (=The "little" neat scripting Language that provides all these nifty little dynamic features of modern Websites. Side-scrolling and other animations, automatic Reloads,... you name it)

Most things that have some kind of Animation or dynamic Functions are done using JavaScript. That is if not using Flash of course (what i personally prefer).

Didn't know that. Then i would really suggest just to take a Template and fiddle around a bit until it looks the way you like it/can use it. Is there any particular Reason that the Flash-Site is so preferable? Are we talking about "cool" Animations here or really a well done Concept/Style?

Is this a public Template? You got any URL or some kind of way to show the Flash-Site or what you want to achieve?

Embedding Flash in Java is hard enough but the other way round is afaik not possible.

And before you start to split your flash thing in multiple parts to put around your Applet i'd suggest you just do HTML+CSS (which i think is the intended purpose of letting you create a website in the first place?).

There are some pretty awsome Templates out there. Go get 'em 
(EDIT: Writing your own would be the best option though... You just don't have to invent the wheel over and over again. Use the best parts and ditch the rest)