Hi, I chose to TCP socket, because I had written a multithread server based on TCP socket before I decided to take the test. I wanted to reuse my work and I believed it will make the network database server open to other programing language. But when I was preparing the essay test, I found myself in an embarrassment situation. Serialized objects over TCP socketcannot be open to other programming language, because serialized objects is not a public protocol. It is a native J2SE mechanism. But I had already upload my submission to the database and in the main choices file I had said that I use Socket to make the network server open to other programming language. When I taken the essay test, I just said that I use serialized objects over TCP socket because it is fast than RMI. Therefore I guess it is the reason that I lost 10 point in my General Considerations section. Hope this will help. Good luck!