This week's book giveaway is in the Cloud/Virtualization forum. We're giving away four copies of Learning OpenStack Networking: Build a solid foundation in virtual networking technologies for OpenStack-based clouds and have James Denton on-line! See this thread for details.
I'm not sure about IntelliJ plugins, but the OpenJPA system has a set of batch utilities that can scan a schema and generate Java class definition files. I've used it many times to adopt pre-existing databases for JPA. In fact even before JPA, since they were originally part of Kodo JDO, which is one of JPA's ancestors.
An IDE is no substitute for an Intelligent Developer.