title: Retrieving JPA Entity List and metadata
body: <p>I wanted to know if there is a way to get all the Entities classes and their metadata for a specific persistent unit in JPA.</p>
  
  <p>By metadata I mean not only the fields, but also their column name, lenght, precision, datatype, and also the table name and anything that I can get. I tried with the metamodel but I think that's more for the JPQL queries only.</p>
  
  <p>I need to be able to show the user all the active Entities for some PU, and I don't want to hardcode them in some array or in a database, I want the API to tell me what Entities does it have. And also, if it is possible, get the managed instances for every entity.</p>
  
  <p>I guess I could try using reflection to get all the classes with the @Entity annotation, but it would not be pretty, and it would be harder to know which belongs to a specific PU, so if the api already exposes this info it would be great.</p>
  
  <p>I would prefer a JPA compliant solution but if not possible, an Hibernate or EclipseLink specific answer would do it.</p>
  
  <p>Thanks!</p>