In our company we use WebSphere Application Server to hold web application but it is not available for developers because of license issue.
We have been using Tomcat to test the web application and hope that it works fine with WebSphere on production phase.
I would like to adapt spring framework into our POJO web application servlet with oracle JDBC and I am not sure of how much WebSphere support spring framework. I checked with the IBM site and it seems not realistic to test web application with tomcat because there are some pitfalls in using spring in WebSphere as a container.
http://www.ibm.com/developerworks/websphere/techjournal/0609_alcott/0609_alcott.html
P.S. I have no experience in using spring or any java framework.