new HashSet<PersistenceUnitDescriptor>();
// step #1: PUs referenced by EJBs
for (Object o : application.getEjbBundleDescriptors()) {
EjbBundleDescriptor bundle = EjbBundleDescriptor.class.cast(o);
allPUs.addAll(bundle.findReferencedPUs());
}
// step #2: PUs referenced by Web components
for (Object o : application.getWebBundleDescriptors()) {
WebBundleDescriptor bundle = WebBundleDescriptor.class.cast(o);