Re: J2SE and J2EE difference
zhangyuewuliu@gmail.com wrote:
Hi,
I have a few confusions about J2SE and J2EE. If you can help to
clarify, that would be great.
1. What is the biggest difference between J2SE and J2EE? Is it just
that J2EE contains a few more extras libraries?
JSE (they dropped the "2") is the core Java language and APIs. JEE (they
dropped the "2") is a collection of specifications for web-enabled development.
The phrase "just that X contains a few more extras [sic] libraries" makes it
sound like libraries aren't important. They are. It isn't "just" that JEE
specifies more libraries, it's what those libraries can do.
2. When I installed Java EE 5, the JRE installed is Java SE Run Time
library 6. Does it mean that J2EE and J2SE uses the same JRE?
The JRE is an implementation of JSE. Let me say that again: the JRE /is/ your
JSE. JSE doesn't "use" the JRE - the JRE is your JSE. Similarly, Tomcat or
JBoss or Sun App Server or WebSphere or Oracle App Server or BEA ... is your JEE.
3. Another question is regarding the J2EE implementations, like JBoss
and Sun Java System Application Server. Where does this piece come
into play? What is it used for? If I wrote an application with J2EE,
do I only need the JRE to run it, or I need the application servers to
run it?
JBoss or Tomcat or whatever is your JEE. Without one (or more) of those you
don't have JEE. You need an application server to run such an application.
Put another way, to run JEE you must have JEE.
There are tutorials on java.sun.com. Also, GIYF and WIYF.
--
Lew