The best place to start is by reading some books and downloading some free code. There are basically 4 major parts to J2EE
(1) Web front-end technologies (Servlet/JSP)
(2) Back-end Business logic technologies (JDBC/EJB)
(3) Messaging technology (JMS)
(4) Enterprise access technology (JCA)
There are many good books on
servlets and
JSP. Reading Jason Hunter's Servlet book (
http://www.amazon.com/exec/obidos/ASIN/0596000405/qid=1005050284/sr=8-1/ref=sr_8_3_1/104-3422779-4627908) is one good way to start.
For EJB's and JMS I'd recommend Richard Monson-Haefel's books on the subject (
http://www.amazon.com/exec/obidos/ASIN/0596002262/qid=1005050337/sr=1-1/ref=sr_1_2_1/104-3422779-4627908) and (
http://www.amazon.com/exec/obidos/ASIN/0596000685/qid=1005050337/sr=1-2/ref=sr_1_2_2/104-3422779-4627908)
One of the things you will need if you are going to learn J2EE is an application server. Working for IBM, I'm partial to the WebSphere application server.
If you buy my book (below) you'll not only get a full explanation of the basic J2EE technologies of Servlet/JSP and EJB, but you'll also get a copy of WebSphere and a copy of the VisualAge
IDE to practice on...
Good luck.
Kyle
------------------
Kyle Brown,
Author of
Enterprise Java (tm) Programming with IBM Websphere
See my homepage at
http://members.aol.com/kgb1001001 for other WebSphere information.