Best strategy for a multiplayer realtime server?

Hello,

I’ve a problem and I need your help. I’m developing a multiplayer realtime game and I need the advice of any expert in server realtime programming. I’m an expert in client programming and even though I’ve done the basic server I need in Java, I don’t know how to face problems like supporting a big demand of users.

Some characteristics about the needs of my project:

• The behaviour of the server is similar to a chat system.
• There won’t be any access to hard drive to save/read anything.
• The amount of heap memory foreach thread managing a room up to 10 players is almost non-existent.
• In each room thread there is no compute intensive calculations because its behaviour is basically to broadcast message between players.
• Each thread is going to broadcast every 100 millisecons packets around 5 Kbytes of information.
• The server is done in Java.

Thanks