Popular application server

Which Application Server is commonly used by companies? What application servers have free downloaded version, so that we can use and test it out?
Any suggestion would be of great help.

Hi,
There are many application and web servers on the market and it's a daunting task to choose which one is right for you. Fortunately, most are now certified by Sun as J2EE compliant.
If you're after a JSP/Servlet runner, I would recommend that you take a look at something like Tomcat ( http://jakarta.apache.org ) or JRun ( http://www.allaire.com ).
If it's an application server that you need (to run JSPs, servlets, EJBs, JMS, etc), some popular ones are JBoss (free from http://www.jboss.org ), BEA WebLogic ( http://www.bea.com/products/weblogic/server/index.shtml ), IBM WebSphere ( http://www-4.ibm.com/software/webservers/appserv/ ) or iPlanet ( http://www.iplanet.com/products/iplanet_application/home_2_1_1n.html ).
Of course there are many, many more...
Hope that helps!
Regards
Simon
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Simon Brown
Co-author of Professional JSP 2nd Edition
[This message has been edited by Simon Brown (edited July 19, 2001).]

Thank you, Simon. Your suggestions were of great help. I would like to learn about EJB in J2EE environment. May be I have to choose any one of IBM's WebSphere/BEA WebLogic/IPlanet etc.

Alam,
If you are working in a Windows environment and want a "quick" solution, I would suggest the BEA WebLogic server solution. I was asked by my employer to install and evaluate it and was very pleased. It only took an hour or so to install and setup and I was developing/testing JSPs on it shortly ofter that.
Enjoy,
Robin

I have to agree. The WebLogic server is easy to install, comes with a 60-day evaluation license, and is well documented. It's built on 100% java. You can have it fully installed and serving JSPs in under an hour.
The download link is: http://commerce.bea.com/downloads/weblogic_server.jsp

What's the difference betweeen application servers and web servers?

This will start to answer that question as well as giving you a slightly longer list of app servers...
http://serverwatch.internet.com/appservers.html
(note that they are not all J2EE (java) complient servers)
Dave

Originally posted by Alam Vin:
Thank you, Simon. Your suggestions were of great help. I would like to learn about EJB in J2EE environment. May be I have to choose any one of IBM's WebSphere/BEA WebLogic/IPlanet etc.

For learn you can use J2EE Application Server (Reference Implementation) with good tutorial (http://java.sun.com/j2ee)