public Builder setNotificationEndpoint(
        com.google.apps.events.subscriptions.v1.NotificationEndpoint value) {
      if (notificationEndpointBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        notificationEndpoint_ = value;
      } else {
        notificationEndpointBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000080;
      onChanged();
      return this;
    }
<pre>
Required. Immutable. The endpoint where the subscription delivers events,
such as a Pub/Sub topic.
</pre>

<code>
.google.apps.events.subscriptions.v1.NotificationEndpoint notification_endpoint = 7 [(.google.api.field_behavior) = REQUIRED, (.google.api.field_behavior) = IMMUTABLE];
</code>
java-workspaceevents/proto-google-cloud-workspaceevents-v1/src/main/java/com/google/apps/events/subscriptions/v1/Subscription.java