java - Container-Managed Transactions -


just clarification on understanding of how container-managed transactions(cmts) work in jpa -

cmts spare application effort of beginning , committing transactions explicitly right?

cmts can applied session , mesage-driven beans , not pojos?

my rationale above questions - i'd know how access entity java-se application java-ee. need 2 separate persistence unit?

i allow myself rewrite answer cause wasn't clear @ , worse, things wrongs.

fact (and i) mixing ejb , jpa terminology.
jpa talking entity beans. session bean (including cmt , bmt) part of ejb spec.
in jpa talk container-managed , application-managed entity manager linked jta or resource-local persitence unit.

here relevant part of jpa spec :

a container-managed entity manager must jta entity manager. jta entity managers specified use in java ee containers. application-managed entity manager may either jta entity manager or resource-local entity manager.

[...]

both jta entity managers , resource-local entity managers required supported in java ee web containers , ejb containers. within ejb environment, jta entity manager typically used. in general, in java se environments resource-local entity managers supported.

[...]

an entity manager transactions controlled through jta jta entity manager. jta entity manager participates in current jta transaction, begun , committed external entity manager , propagated underlying resource manager.`

[...]

when container-managed entity manager used, lifecycle of persistence context managed automatically, transparently application, , persistence context propagated jta transaction

so need define 2 persistence unit if want use jta (weather or not container-managed) entity manager in java ee application.


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