I was searching for an eclipse plugin to reverse engineer the code developed by salto-db-generator for hibernate. I found slime eclipse plugin, that automatically support many features like use-case diagrams, class diagrams etc.
This can be downloaded from http://www.mvmsoft.de/content/plugins/slime/index.htm
A getting started page is found at http://www.mvmsoft.de/content/plugins/slime/help/gettingstarted/installation.htm
Please find attached a class diagram generated by the plugin
automated UML diagram