What is the difference between J2SE & J2EE.. Many thanks...
J2SE (standard edition) is just the normal specification of Java. J2EE (enterprise edition) is Java with all sorts of add-ons for enterpris-y things like:
- Enterprise JavaBeans;
- Java Persistence API;
- Servlets;
- Java Server Pages.
(not an exhaustive list, more detail available on Wikipedia). You generally get J2SE when you download the SDK (for development) or JRE (for running Java applications).
On the other hand, you generally get all the J2EE goodies when you start using IBM Websphere Application Server, or JBoss, or another enterprise-class application server.
Oracle/Sun refer to these now as Java SE and Java EE and you can download the Oracle Java EE 6 SDK here. The JSR for Java EE 6 is here.
You can just know this for short: J2SE is for desktop applications and it is the core of Java. J2EE is for web applications which include JSP & Servlet, EJB, Webservice and they are kinda extensions. You can use them when install a Servlet container (Tomcat) or a JPA provider (Oracle Toplink, Hibernate) or an entire Web application which includes servlet container, JPA provider such as JBoss, GlassFish.