1/31    Can someone explain (with minimal buzzword usage) what a java
        application server (like websphere) is and why companies use them?
        \_ This might be wrong, but it will probably give you a general idea:
           They make java beans and servlets easier.  Java beans are of 2
           colors:
           Entity beans, which have attributes that map to database rows (w/
           associated getters/setters + other custom methods); and session
           beans, which save state between page loads (easier to deal with
           than cookies).
           Servlets are tiny java classes/methods embedded in html files.
           \_ Servlets can be automatically generated from JSP files which
              have java embedded in HTML, but that's not all a servlet is.
        \_ An application server is just an environment for code
           to run under. In addition, app servers provide some
           capabilities like monitoring, reliability/failover,
           security, etc.
           Some types of applications require an application server because
           they need an execution environment for the code (e.g., web-based
           applications or EJB applications).
           Companies use app servers either because they type of application
           they are writing requires one or because they need (or think they
           need) the additional services an app server provides.
        \_ The notion is that a lot of server-based applications have a very
           similar core: multithreading, database connectiviy, directory
           connectivity, load-balancing, management, failover, transaction
           management(especially distributed transaction mgmt),etc...The idea
           is that if you accept certain limitations on your design, you can
           get these features without having to implement them yourself.
        \_ Duh, he said minimal buzzwords.  Application Server is nothing
           but a sophicasted midlleware that lies between your client and
           backend server.
           \_ buzzwords: middleware, client, and backend server.
              \_ He didn't say no buzzwords.  Learn how to read.
                 Even with 3, that is a lot fewer than 20.  And that is
                 if you consider client and backend server buzzwords.
        \_ what's a good way to learn to work with application servers if
           I've never used them before (but I'm good with java)? thanks for
           the answers, btw. -OP
        \_ Read the introduction to the book "Enterprise JavaBeans, 3rd Ed."
           on http://amazon.com or in a bookstore.
        \_ CGI PERL SCRIPTS INSTANTIATE NEW PROCESSECES EVERY TIME THEY
           ARE RUN, JAVA APP SERVERS DONT END OF STORY
           \_ bitch calm down!
              \_ you meant... "stupid bitch calm down!" appservers are
                 much more than CGI replacements and don't necessarily
                 have anything whatsoever to do with HTTP (ejb, jms,
                 soap/.net, etc).  since most business is just some
                 process and software is good at modeling processes,
                 most modern businesses are heavily automated with
                 software (sap, peoplesoft, seibel, etc.).  app
                 servers provide a platform to build business apps
                 on top.  if you want the warehouse to tell the
                 e-commerce site that you are out of a product, you
                 probably want reliable, guaranteed message delivery
                 so you use an appserver with messaging middleware
                 (jms is the java standard interface for messaging).
                 \_ Anyone who has been in an organization that has
                    implemented SAP or PeoplesSoft knows that they're
                    actually very poor at modeling processes.  They're
                    good at getting organizations to change their processes
                    to fit the business software.  -tom
                 \_ i never said java app servers are replacements for CGI
                   nor did i say they only have to do things with HTTP. Jerk.
                   \_ yes you did CGI-end-of-story retard.  learn to
                      communicate.
                        \_ plus, if you have mod_perl installed, CGI perl
                           scripts don't instantiate new processes.  -tom