code: public Class<?> getEJBPrimaryKeyClass(J2EEName j2eeName) {
          Class<?> rtnPKeyClass = null;
          BeanMetaData bmd = internalBeanMetaDataStore.get(j2eeName);
          if (bmd != null) {
              rtnPKeyClass = bmd.pKeyClass;
          }
          return rtnPKeyClass;
      }
docs: Returns the primary key class associated to the input j2eeName or
  null if j2eeName or primary key is not specified.
  
  @param j2eeName unique identifier for EJB
  @return Prmiary key class.