code: public synchronized static Session getSession() {
          if(session == null){
              Properties properties = IOUtil.loadProperties("jdbc.properties");
              session = getSession(properties);
          }
  
          return session;
      }
docs: Returns a session configured with the properties specified in the "jdbc.properties" file.
  
  @return {@link Session}
  
  @throws ConfigurationException if the configuration can't be loaded