I am quite confused about creating driver definition for h2 database. First question is: Shouldn't be h2 part of "Available driver templates" (or Vendor filter or whatsoever) list ???
I tried to use "Generic JDBC driver" option for this and basically I wasn't able to do that, because of following error:

An error has occurred. See error log for more details.
Widget is disposed

Reproducible by following steps:
1. Choose "Generic JDBC driver"
2. Click "Add" button. (you need to choose db type again)
3. Switch to "JAR list" tab.
4. Add h2 driver jar (e.g. the one from EAP 6.1).
5. You need to specify "Drive class definiton".
6. Go with "org.h2.Driver".
7. Notice the error.