As discussed on the dev mailing list ...
I found that the following mapping:
public class AnnoTest1
This results in a warning message , but it is allowed. This JIRA will be used to detect this condition and fail fast.
 297 TestConv WARN [main] openjpa.MetaData - OpenJPA cannot map field "test.AnnoTest1.o" efficiently. It is of an unsupported type. The field value will be serialized to a BLOB by default.