This unit describes how we use Java to program internet-based applications, such as those associated with e-commerce or internet chat rooms. Amongst other topics, we will look at how the internet is structured, the roles of clients and servers, and how they are programmed using sockets. This unit will also show how to make use of threads to enable servers to deal with multiple clients. To complete the activities in this unit and to gain a full understanding of the subject this book recommends the use of other resources