Often architects are faced with situations where they have to decide on open source and commercially available technologies.
Spring (lightweight application container) and Hibernate (persistence framework) are popular opensource projects that claims to even be a substitute for J2EE container. Here is a good article on how to get the most of these open source technologies along with popular comercial application server from IBM – WebSphere.
http://www.ibm.com/developerworks/websphere/techjournal/0609_alcott/0609_alcott.html