They're things you don't need to worry about until after you learn Java a
bit more.
>From: "Tim Nicholson" <[EMAIL PROTECTED]>
>Subject: [jdjlist] Re: J2EE, Tomcat, JBoss, etc.
>Date: Mon, 23 Sep 2002 18:22:18 +1000
>Can you explain what the following are :-
>
>1) JBoss
An open source J2EE container; very nice, but the docs suck rocks. They're
also very strident, very "We're open source, so open source rules the world!
Send us money."
>2) Orion
A J2EE container from Sweden, licensed by Oracle as the heart of their
backend J2EE server. (IIRC, they use Tomcat as the servlet container for
backwards - err, backward compatibility, and Apache for static content. Why?
I couldn't tell you, since Orion tends to be far better/faster than Tomcat,
and it's very comparable to Apache in speed for static content as well.)
>3) Tomcat
An open source servlet container, given to Apache by Sun. It's the
"reference implementation" of the servlet spec. As such, its location on
Jakarta is a little misleading; it's not open the way that, say, Apache is,
where Apache only has to conform to the communication spec (HTTP) and inside
it can do whatever it wants when it wants to, depending on the desire of the
coders; Tomcat has to conform to the servlet spec literally. It also fails
to do so in a number of places. (Search the web.) This, plus its poor
performance (moderately slow servlets, which isn't a sin, and HORRIBLE JSP
performance, which probably is), make it a great container for people who
don't really like JSP and/or servlets. It's also VERY popular among the
newbies.
>4) J2EE
A set of enterprise APIs from Sun. Covers distribution and messaging, as
well as service lookups and RPC mechanisms.
>5) JNDI and
A service lookup mechanism.
>6) JMS containers, in
in? JMS is a MOM interface; MOM is "message-oriented middleware," a way of
invoking potentially asynchronous events.
>7) EJBs
Enterprise Java Beans, basically a way of packaging RPC and/or remote data
objects. Went in heavy vogue for a while; when the buzz died down some,
other RPC mechanisms took the lead and now EJB is in its rightful place as
yet another tool in the toolbox. Like a torque wrench, when you need them
they're PERFECT. Other than that, they kinda suck.
>8) JSP
Viewed VERY simply, servlets - when generating HTML - embed the HTML in Java
code. JSP goes the opposite direction, potentially embedding Java code in
HTML. Sounds kicky. Isn't always. Gets castigated by a lot of wankers with
axes to grind in other directions ("GAHHH! JSP SUCKS! I HATES IT! I HATES
IT! I HATES IT FOREVER! Use Velocity."), which is unfair to JSP; it can
indeed suck quite a bit, but it can also be written quite elegantly and
correctly. Also, since JSP depends quite a bit on the deployment engine
used, people MEAN to say "GAHHH! TOMCAT SUCKS! I HATES IT! I HATES IT! I
HATES IT FOREVER! Use Orion." but use the incorrect form. You find these
people discover what JSP custom tags are, crank them up in Tomcat's rather
poor implementation, and think "Gee, JSP is sssslllooooowwww." Sorry; it's
Tomcat in that case, since for tags, especially, it's got poor performance.
>So what are these ? And can you recommend any learning materials (websites,
>books)
>for beginners in these technologies ?
As always, start at java.sun.com, and look at what you need.
>I am someone who is just starting to learn java and I don't know about any
>of these additional things ?
If you're just starting, you don't need them. Learn Java instead.
-----------------------------------------------
Joseph B. Ottinger [EMAIL PROTECTED]
http://enigmastation.com IT Consultant
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