- <0.1.9> when there is no @Entity class in the whole class path, the default persistence.xml will include a
  <class>null</class>
  
- [high] provide an update fields interface for entity that take a Map of changes, and the map value accept a Closure of {currentValue, entity -> }

- [high] use Hibernate plugin instead of including Hibernate libraries
    plugins.hibernate=1.1-beta3

  see http://jira.codehaus.org/browse/GRAILS-4005

- [high] register persist, refresh, flush, delete and any relevant JPACategory methods to any detected Entity Beans in Grails

- [high] utilize Grails' transaction or transaction configuration for the JPAContextHolder

- enhance Groovy JPA interface
    allow jpa{ } static import usage
    add more constructor for JPA? e.g. new JPA(em)

- support constructing with EntityManagerFactory
    emf support is taken out from project in the initial release to simply the implementation until it is more stable
    and mature

- [low] support Multi-thread operations
    e.g. when saving data, a PooledJPA instance could be created to read data in multi-threads
    sequence could managed by a 'group' parameter. e.g.
       entity.persist(group:1)
       entity.execute(group:1){
        entity.'name' = 'updated name'
       }
       entity.delete(group:1)

    transaction issues need to be managed

  - [low] provide a query snonym for executeQuery, or an enhanced Groovy way to do query

Groovy JPA
  - perform automatical class convertion for the id field of getEntity()
    require:
        prepare a registry of entity bean class with primary key information (either load upon startup or lazy-load)

    benefits:
        users need not to cast the id field explicitly when using getEntity(id:xxx)


  - add EntityClass.getEntity(id:xxx) method.
    benefits:
        when using em.getEntity(), users need to supply a em.getEntity(id:xxx, class: EntityClass.class), why not just
        EntityClass.getEntity(id:xxx) similar to GORM finder method.