Here is a common problem. You have to write an web-based email, im, ssh, xmmp, SMB, etc. client which must connect to a server other then the originating one. What do you do then? Hint: You cannot use Java!
Well, due to the fact the the browser has no idea how to spawn a tcp socket, you are stuck in the proxy-land. Typically you will write an application that will do a lot of transcoding and state management. [...]
