code: public ListSubscriptionsPagedResponse listSubscriptions() throws Exception {
      // [START pubsub_list_subscriptions]
      try (SubscriptionAdminClient subscriptionAdminClient = SubscriptionAdminClient.create()) {
        ListSubscriptionsRequest listSubscriptionsRequest =
            ListSubscriptionsRequest.newBuilder()
                .setProject(ProjectName.of(projectId).toString())
                .build();
        ListSubscriptionsPagedResponse response =
            subscriptionAdminClient.listSubscriptions(listSubscriptionsRequest);
        Iterable<Subscription> subscriptions = response.iterateAll();
        for (Subscription subscription : subscriptions) {
          // do something with the subscription
        }
        return response;
      }
      // [END pubsub_list_subscriptions]
    }
docs: Example of listing subscriptions.