Review of IntelliJ IDEA, a Java IDE
The commercial version adds numerous features, including UML diagramming, code coverage analysis, JavaScript debugger, support for other languages including Ruby and Python, and version control clients for commercial systems such as ClearCase and Team Foundation Server.
Even more important, the commercial version adds framework support for everything from JavaServer Faces and Servlets to Google Web Toolkit, Struts, Spring, Hibernate and Tapestry, and server support for Tomcat, JBoss, WebLogic, WebSphere and others. Enterprise developers will need the commercial edition.