Java APIs

Hi All,
I am new to socket programming. Can anybody help me out in this.
I need to develope an application which will have client server communication.
Both are on diff. machines.The prerequisite is first client need to test whether server is up and running if server is up and running then client will recieve a notification. After this notification client will send the actual required data to the server.On completing the task from server side, client will again get the accknowledgement.
This client server communication is divided in 3 parts-
1) some generic classes for making connection,releasing connections etc.
2) Listner classes as we use in AWT,Swing
3) Actual implementation/definition of class which user will use.

Can anybody tell me how to go ahead for this requirement ASAP.

Thanks in advance.
Neha