I am using Tomcat for hosting my Java Web and Web Service applications for a long time now. Mostly for Spring and Grails applications at the moment.
Lately in one project a discussion came up, about how deal with dependencies/libraries in Tomcat production environments:
In my projects I am deploying big WAR files holding all the required dependencies for the application in WEB-INF/lib folder. The only things I put in the tomcat/lib folder are the JAR files for JDBC connections managed by tomcat.
The customer has a long history with WebSphere and thinks the container should hold most of the the required dependencies. So they want to put JAR files for used frameworks or WebService API's (like Metro) in the tomcat/lib folder and have skinny WAR files.
The problem with that solution in my opinion is that if you have an application that requires another version of a dependency that is already included in the tomcat/lib folder you can get errors and strange behavior.
Is there some best practice or official document that talks about this issue? What is your opinion about this?