code: public Boolean ruleExists(String topicPath, String subscriptionName, String ruleName) throws ServiceBusException, InterruptedException {
          return Utils.completeFuture(this.asyncClient.ruleExistsAsync(topicPath, subscriptionName, ruleName));
      }
docs: Checks whether a given rule exists or not for a given subscription.
  @param topicPath - Path of the topic
  @param subscriptionName - Name of the subscription.
  @param ruleName - Name of the rule
  @return - True if the entity exists. False otherwise.
  @throws IllegalArgumentException - path is not null / empty / too long / invalid.
  @throws TimeoutException - The operation times out. The timeout period is initiated through ClientSettings.operationTimeout
  @throws AuthorizationFailedException - No sufficient permission to perform this operation. Please check ClientSettings.tokenProvider has correct details.
  @throws ServerBusyException - The server is busy. You should wait before you retry the operation.
  @throws ServiceBusException - An internal error or an unexpected exception occurred.
  @throws InterruptedException if the current thread was interrupted