I have a lot of experience with Java Application Servers, from Weblogic to jBoss 5,6,7 and Glassfish. I’m a Java and J2EE Trainer too. So, I’m not here to make an argument against the use of Java Application Servers, I use them every day, however I must say some things that I really dont understand (from a user/developer perspective) about Java Application Servers:
Why Java Application Servers don’t isolate a deployed application? How many times are you deploying an application and you have to configure, customize, remove jars, add another’s jars, create additional files just because the application server already has some of the jars you use in your application? For instance, in my team, we are migrating sites and web services from weblogic and its a nightmare, jboss already have some of the jars, and at deployment time throws exceptions that are not so easy to understand at first sight. (like logging jars – in our case slf4g with logback) If an application could be isolated like a file system application its isolated in an operating system like linux or MAC OS these problems dont even existed! I just wanted to deploy my application with the jars I need, and don’t think about what jars the application already have.
I have experienced deploying applications in Microsoft IIS and in Java application servers. Using Microsoft Servers its much more easy than using similar java products. Usually, when starting and developing Microsoft products I spend 80% of the time focused in developing and testing the product, and the other 20% finishing configuring and deployment. With Java Application Servers, first you must study the application server, know about several XML files with specific names, to configure datasources, jms queues, etc. Then you hope that exists some eclipse plugin or netbeans plugin that really works. I have experienced plugins for weblogic and jboss but sometimes when you deploy an application its just a view for your eyes, the application doesnt get really deployed to the application server, so I have to go to the localhost website, and deploy it. The inverse its also true. So, 80% configuring and preparing, learning and training and the rest 20% of time developing.
Don’t get me wrong, my experience its divided between these two worlds (Microsoft and Java), I like Java, after all the configuration its done everything will work as expected, but its a really tough job to put everything to work at first in Java Application Servers World!