Building 3-tier systems using Java

[M54]

Hi.

I wish to build three tier systems in Java, including a web presentation layer, a BLL that's located on a different computer than the one that hosts the web site and a database which is located on a different computer than the one of the BLL or presentation layer. I already have lots of knowledge and experience with Java (J2SE) and Swing. I have also studied SQL.

What technologies / tools do I need to study in order to build a three-tier system using Java? I'd appreciate it also if you can please specify how these tools interact with each other and why I need them in the first place.

Thanks in advance.

[Tolls]

Web services of some description?
Not sure about separating the business layer entirely like that if you've not done this before. That throws up a whole load of problems when it comes to tracking sessions. OK for sessionless stuff.