Setting Up a Java Web Server on Linux

Question

Greetings,
After a lot of reading, I've decided to learn Java server-side technologies (I already know Java (desktop)
but with little experience) in order to develop my database driven dynamic website projects.
However, I'm completed lost between the hundreds of acronyms related to Java and the "thousands" of technologies involved.
Google hadn't help me understand what they really are and how they relate with each other.
Even though is easy to find what they stand for and some faqs/descriptions, it hasn't been enought to clear my mind.
I want my webserver application to do, among other things, the following:
Retrieve Data from a database, do generate dynamic html files.
Story Data on the database, from html forms.
Send automaticly emails for multiple users. (newsletter for example)
E-Commerce.
Html graber/parser (I don't know if this is the right word, I mean a program that for example, goes to a URL with an html
table, and stores that information in a database table, as long as the format didn't change).
Real Time Chat feature.
Database connection pooling, caching, and other important optimizations.
I'm not asking for how to develop or configure this features nor what components and programs, must be installed.
At the moment, I only want to know how to set up a Java solution that will support them when they are needed.
*** Linux ***
I want to set up my webserver on a linux distribution.
In that respect, I don't know if I should choose RedHat or Fedora Core.
I've heard that fedora is better for a webserver (having in mind that Red Hat Enterprise AS/ES aren't free).
But I've read in several sun turorials/webpages references to RedHat (on a J2EE context).
So I'm wondering if is better to go for Fedora or RedHat. Are there pros & cons? They equally support Java?
*** Technologies ***
Then in starts the acronyms problem.
What do I need to install, in what order, for what?
Some aconyms and technologies, I have read about but don't fully understand are the following:
Apache
J2EE
J2EE 1.4 SDK
SUN Java System Application Server Platform Edition 8
J2SE 1.4.2 SDK
SUN Java Enterprise System
Tomcat
Struts
Cocoon
JBoss
I already know J2EE is only a specification. What implements that specification? Sun Java System Application Server?
J2SE SDK? or Tomcat?
What is the role of each technology, namely Apache, Tomcat, Sun Application Server?
What is the Sun Java Enterprise System?
How do Struts, Cocoon, JBoss relate to Java?
Which of these technologies are mutually exclusive (analogous)?
*** Doubts ***
Then, I have some doubts that are keeping me from starting to study seriously the important techonologies, because I don't
want to lose lot's of time and effort learning them to after a dillusion start everything again with PHP (the language
which make me think and read a lot before going for Java). To keep this from happening, I would like to know the following:
I want to use Java for developing websites with commercial/profitable use for my company, in some throught e-commerce,
and in other by banners. I want to do everything by the book, with required licenses.
------ Java is Free?
Is Java Completely Free or it might be possible that at a certain point, when I need some component or library,
multi-machine webserver, performance or security for high-traffic I will see "buy now" instead of "download now"?
For what they may "ask for money"? and what are the disavantages if I can't buy?
For example, "Java System Application Server Standard Edition 8.1 2005Q1" and
"Java System Application Server Enterprise Edition 8.1 2005Q1" cost $2.000 and $10.000 respectively. That is money.
(http://www.sun.com/software/products/appsrvr/index.xml). What are the disavantages if stick to the free edition?
Features like (from sun site)
Standard Edition:
Extends the capabilities of the Platform Edition to provide secure, remote, multi-instance, multi-machine management.
It is aimed at high-volume applications and Web services.
Enterprise Edition:
Further extends the capabilities of the Standard Edition to provide continuous availablity for applications and
Web services. It is aimed at business critical, high value applications and Web services.
Suppose I achive lots of traffic and I keep the free platform edition.
I won't be able to have a multi-machine webserver set up correctly?
What are the drawbacks? How big are the performance penalties?
------ Technologies Availability
Finnaly, I have the idea (I don't know if it's accurate) that there are Sun versions and Open-Source Free versions
of doing or supporting the same Java related thing.
Despite the way I choose to set up a Java webserver, I will always have all J2EE techonolies like:
Java API for XML-Based RPC (JAX-RPC), JavaServer Pages, Java Servlets, Enterprise JavaBeans components,
J2EE Connector Architecture, J2EE Management Model, J2EE Deployment API, Java Management Extensions (JMX),
J2EE Authorization Contract for Containers, Java API for XML Registries (JAXR), Java Message Service (JMS),
Java Naming and Directory Interface (JNDI), Java Transaction API (JTA), CORBA, and JDBC data access API.
I really appreciate some help. I could learn the basics of all this "stuff" before asking. But the point why I'm asking
is precisely not starting to learn something I may won't use. Obviously, I will have to make a lot of reading during maybe
months before writing the first line of code of my projects, but being certain that it will fit my needs.
I will be very thankful if you can enlightme in my fedora/redhat, setup, free/cost and technologies avaibility issues.
Thanks Beforehand,
Pedro Vaz

Answer 1

Apache is a free Web-server.
Tomcat is a servlet (and JSP) container. It can be stand-alone or can be used together with a Web server (like Apache).
J2EE's scope is much wider than the servlet stuff, but a standalone Tomcat is a good starting point to servlets and JSP.
One of our "real-world" applications is run by a standalone Tomcat using POI and Velocity. I did not regret this architectural decision.