Hi Sameer,
I confirm you that Lightstreamer is a perfectly suited solution for the scenario of a quiz contest.
You can look at the
Simple Chat Demo or at the
Basic Instant Messenger Demo for examples of bi-directional comunication from server to clients and from clients to server.
They are both based on a Java Adapter and can be considered a reference example of, respectively: messages broadcast and one-to-one messaging.
Furthermore,
here you can find a modified HelloWorldDataAdapter that polls a mySql db.
