title: Creating a simple LAN messenger
body: <p>I want to create a simple LAN conference-chat style messenger in Java but I have <strong><em>no clue where to start</em></strong>.<br>
  It must have the following features:<br>
  <li> <strong>no permanent username</strong>: the user must be able to type in a username every time he joins but should have a remember me option in case he uses it frequently</li>
  <li> a simple chatroom interface with all the users online displayed on the right and the chat messages in the centre </li>
  <li> a private chat service and a block option</li>
  I <strong>do not</strong> want the ready-made code, I want someone to explain to me where to start and how to go about doing it and the things I should know (like e.g. a text box to enter user name and stuff )<br>
  <em>Just imagine it as being a messenger allowing all the employees in one building to chat with each other</em></p>