Listing all entities in a JPA

Sometimes it may be a usecase scenario to find whether a particular class is an entity managed by persistence context. If you have entityManager or entityManagerFactory you can easily do that :

 Metamodel meta = entityManagerFactory.getMetamodel();
 // or
 Metamodel meta = entityManager.getEntityManagerFactory().getMetamodel();

 // to iterate over all classes
 for (EntityType<?> e : meta.getEntities()) {
  // get entity class
  Class c = e.getJavaType();
  // get entity name as string
  String entityName = e.getName(); //or c.getName()
 }

 // test a particular class is entity
 // will throw java.lang.IllegalArgumentException if not an entity
 meta.entity(inputClass);