// classes and mapping files. From them we get transients and
// access). Metadata read from XML causes new accessors to be
// created and override existing ones (causing them to be un-
// pre-processed. We can never tell what changes in XML so we
// have to do this.
PersistenceUnitReader puReader = new PersistenceUnitReader(factory);
// Step 3 - iterate over all the persistence units and generate
// their canonical model classes.
for (PersistenceUnit persistenceUnit : puReader.getPersistenceUnits()) {
// Step 3a - add the Entities not defined in XML that are
// being compiled.
for (Element element : roundEnv.getElementsAnnotatedWith(Entity.class)) {
persistenceUnit.addEntityAccessor(element);
}