code: public ActiveMqQueue<ID, DATA> init() throws Exception {
          if (connectionFactory == null) {
              setConnectionFactory(buildConnectionFactory(), true);
          }
  
          super.init();
  
          if (connectionFactory == null) {
              throw new IllegalStateException("ActiveMQ Connection factory is null.");
          }
  
          return this;
      }
docs: Init method.
  
  @return
  @throws Exception