Enterprise JavaBeans (EJB) Version 2.1-compliant beans can be assembled only in an EJB 2.1-compliant module, although an EJB 2.1-compliant module can contain a mixture of Version 1.x and Version 2.1 beans.
The EJB Version 2.1 specification mandates that prior to the EJB container starting a findByMethod query, the state of all enterprise beans that are enlisted in the current transaction be synchronized with the persistent store. (This action is so the query is performed against current data.) If Version 1.1 beans are reassembled into an EJB 2.1-compliant module, the EJB container synchronizes the state of Version 1.1 beans as well as that of Version 2.1 beans. As a result, you might notice some change in application behavior even though the application code for the Version 1.1 beans has not been changed.
The following information generally applies to any enterprise bean that currently complies with Version 1.1 of the EJB specification. For more information about migrating code for beans produced with the Rational Application Developer tool, see the documentation for that product. For more information about migrating code in general, see "Resources for learning."