Since OpenMRS 1.9.2 it is possible to use JPA annotations in modules. See more at:
- Univ Call http://connect.iu.edu/p6erdt413mz/ with code at https://github.com/rkorytkowski/openmrs-module-example-social/commit/e004b52d82d2993c3d284fb24d6a6671f2913381
- https://github.com/rapilabs/openmrs-jpa-annotation-test
- Usage in core: https://github.com/rkorytkowski/openmrs-core/commit/416ca5addf1c50ba65c6982fc55aaceb142d2e44