jpa-2.0

In the spirit of type safety associated with the CriteriaQuery JPA 2.0 also has an API to support Metamodel representation of entities. Is anyone aware of a fully functional implementation of this API (to generate the Metamodel as opposed to creating the metamodel classes manually)? It would be awesome if someone also knows the steps for setting this up in Eclipse (I assume it's as simple as setting up an annotation processor, but you never know). EDIT: Just stumbled across Hibernate JPA 2 Metamodel Generator . But the issue remains since I can't find any download links for the jar. EDIT 2:

When they appear on a field/getter of an @Entity , what is the difference between them? (I persist the Entity through Hibernate ). What framework and/or specification each one of them belongs to? @NotNull is located within javax.validation.constraints . In the javax.validation.constraints.NotNull javadoc it says The annotated element must not be null but it does not speak of the element's representation in the database, so why would I add the constraint nullable=false to the column? Ryan Stewart @NotNull is a JSR 303 Bean Validation annotation. It has nothing to do with database constraints

I am wondering if it is possible using annotations to persist the attributes map in the following class using JPA2 public class Example { long id; // .... Map<String, String> attributes = new HashMap<String, String>(); // .... } As we already have a pre existing production database, so ideally the values of attributes could map to the following existing table: create table example_attributes { example_id bigint, name varchar(100), value varchar(100)); JPA 2.0 supports collections of primitives through the @ElementCollection annotation that you can use in conjunction with the support of java