Joe Daly wrote:ok but does what Application server i use effect how i should code?
No. In fact, doing so is a poor practice (unless you have a really really really good reason to do otherwise).
and whats the difference between a application server and a application server container
There's no such thing a an "application server container".
The term "application server" means different things to different people.
Generally though, an "app server" is one that has some sort of application engine that allows dynamic content to be generated and for code to be executed on the server. In the case of Java web apps, that's any server with a "servlet container".
A servlet container is the component of a web server that runs servlets.