hi, i'm new in j2ee, can someone please guide howto i start learning j2EE ? - what are the tools or software i need to download and so on ? - do i need to download J2EE 1.4 from sun ? is it use for testing or what? what is the different between J2EE1.4 and jBoss, wealogic ?
You need an [j2ee] application server, the above tutorial from Sun explains (they use their own application server).
J2EE is a set of specifications, which the tool venders comply with when they produce their products. The companies Sun [ONE], JBoss [Jboss], BEA [WebLogic], IBM [WebSphere] have J2EE application servers.
If you already know Java, then I'd recommend learning Servlets and JSP (and maybe JSF) before tackling EJB - especially since the current Entity Beans persistence model is being completely written off in favour of a more lightweight persistence solution similar to the JDO (Java Data Objects) standard.
Once you know at least a little Servlets + JSP (+JSF), then look at Session Beans, and maybe look at JDO2. I wouldn't waste any cycles on Entity Beans in EJB 2.1, since they're going the way of the dodo with the EJB 3 and J2EE 5,