I want to deploy two jars in my server/messaging/deploy folder, each having a persistence.xml file and also each having a stateless session bean having the @PersistenceContext(unitName="myUnit"). I call a WebMethod in one of my stateless beans, which in turn calls a WebMethod in the other stateless bean (which has been obtained using the @EJB annotation). But, I get a PersistenceException - TransactionRequiredException, when it tries to persist anything in the nested WebMethod call. I understand that nested transactions are not supported by the EJB spec. But I would sincerely appreciate any inputs on what is the best way to have an API in one EJB Bean call another API in another EJB bean, each having their own separate persistence units.