void function ( ) { }
creates an entity manager factor . repeated invocation of this method will do nothing i.e. an entity manager factory ca n't initialize twice . concode_field_sep EntityManagerFactory factory concode_elem_sep ThreadLocal<EntityManager> entityManager concode_elem_sep Logger log concode_elem_sep String PERSISTENCE_UNIT concode_field_sep void beginTransaction concode_elem_sep void commitTransaction concode_elem_sep void rollbackTransaction concode_elem_sep void commitAndCloseTransaction concode_elem_sep EntityManager currentEntityManager concode_elem_sep void shutdown concode_elem_sep void closeEntityManager concode_elem_sep EntityTransaction getTransaction