I recently decided to upgrade some Hibernate based components from 3.5.6 and wished to go "all the way" to 4.1, but I soon realised it was not going to be as easy as I'd hoped.

After making the necessary adjustments from https://community.jboss.org/wiki/HibernateCoreMigrationGuide40, I upgraded hsqldb from 1.8.x to 2.2.x and attempted to run my tests. After the third unit tests, the test hanged. I turned on all debugging symbols and and discovered that it hanged while attempting to drop a constraint on one of the tables.

Before I start posting any code I'd like to know if anyone has encountered these difficulties? The upgrade to 3.6.10 branch went without a hitch.