Performant Multi Threading with Clients on a socket

Question

At the moment I have a project where we develop a Java Texas Holdem Application. Of course this Application is based on a client server socket system. I am saving all joined clients (I'm getting them with socketServer.accept() method) in an ArrayList . At the moment I make one thread for each joined client, which permanently checks if the client send any data to the server. My classmate told me it would be way better if I create one big Thread, that iterates through the whole Client ArrayList and checks every Client inputstreamreader . Should I trust him?

Answer 1

Creating a thread per Socket isn't a good idea if your application will have a lot of clients.

I'd recommend into looking into external libraries and how they handle their connonections. Example: http://netty.io/ , https://mina.apache.org/

Answer 2

Both approaches are not feasible. Having a thread per connection will quickly exhaust resources in any loaded system. Having one thread pinging all connections in a loop will produce a terrible performance.

The proper way is to multiplex on the sockets - have a sane number of threads (16, why not), distribute all sockets between those 16 threads and multiplex on those sockets using select() variant - whatever is available in Java for this.