code: public Subscription getSubscription(String subscriptionId) throws Exception {
      // [START pubsub_get_subscription]
      try (SubscriptionAdminClient subscriptionAdminClient = SubscriptionAdminClient.create()) {
        ProjectSubscriptionName subscriptionName =
            ProjectSubscriptionName.of(projectId, subscriptionId);
        Subscription subscription = subscriptionAdminClient.getSubscription(subscriptionName);
        return subscription;
      }
      // [END pubsub_get_subscription]
    }
docs: Example of getting a subscription.