code: @Override
      public void shutdownModule() throws ModuleShutdownException {
          super.shutdownModule();
  
          for (Map.Entry<String, ConnectionPool> e : h_ConnectionPools.entrySet()) {
              e.getValue().close();
          }
  
      }
docs: <p>
  Closes all connection pools. This method overrides
  <code> shutdownModule()</code> .
  </p>
  
  @throws ModuleShutdownException
  If the close operation for the connection pool(s) fails.