The published javadoc of versions 4.1 and 4.2 doesn't look nice at all, because it uses a Java 6 stylesheet and the doc has been generated with Java 7.
I've been asked to create this JIRA via Twitter (https://twitter.com/Hibernate/status/388552572824735744) and to contribute a fix for the CSS, but The fix seems to exists for 6 months in the Hibernate gihub repo: https://github.com/hibernate/hibernate-orm/commit/a906d1ffb244d5ad8732a16f3756233da0e15b12

The fix should just be applied to the already published javadoc.