I use Spring Data JPA. It uses the Metamodel to create repository beans. This triggers a connection to the ObjectDB server. It happens on every start of the Context. If it fails the application isn't available at all. I had the situations multiple times that my database server took longer to boot after a power outage than the tomcat machine. This leads to an unusable application until i restart tomcat.
Other JPA providers are able to fetch the Metamodel without connecting to the DB.
I would appreciate it very much if you could change this behaviour in some future version of ObjectDB.