When I run the Server, I enter a random port number, let's say "1111" (tried this with a variety of ports). I get "Server is running." Then I run the Client and for server address, I enter "localhost" (also tried with IP directly) and for port I enter "1111". Then I get back "An error occurred while working with the client." And when I look at the server side I see: "A connection has been established with / An error occurred while communicating with the remote address. Connection with / closed." I can track it to when it's in the constructor for Connection and it's getting the ObjectInputStream. Then I think it's throwing and exception somewhere in there but I can't follow it. Any idea what is going wrong? I can't post all my code here since it's the solution to a task but I can PM you my code if you can help.