The following list shows which services are supported in second-generation runtimes:
| App Engine service | Availability in Java | Alternatives |
|---|---|---|
| App Identity | Available | Migrate to Open ID Connect (OIDC) or Identity Platform |
| Blobstore | Available | Migrate to Cloud Storage |
| Capabilities | Available | No alternatives, see the Google Cloud Status Dashboard or the Google Cloud Console Support page for information on service status |
| Deferred | Available | No alternatives since this API is used with App Engine Task Queues |
| Images | Available | Migrate to Cloud Storage to serve images directly, or use a third-party content delivery network (CDN) or image processing library |
| Logging | Not supported | Use standard logging libraries |
| Namespaces | Available | No alternatives since this API is used with other App Engine services |
| Datastore | Available | Migrate to Datastore client libraries |
| Available | Migrate to SendGrid, Mailgun, or Mailjet for outbound messaging only | |
| Memcache | Available | Migrate to Memorystore |
| Modules | Available | Use environment variables and the App Engine Admin API to obtain information and modify your application's running services |
| Remote | Not supported | Use Cloud Client Libraries to access resources in other projects |
| Search | Available | Migrate to Elasticsearch |
| Task Queues | Available | Migrate to Cloud Tasks for push queues and Pub/Sub for pull queues |
| URL Fetch | Available | Migrate to standard libraries for outbound requests |
| Users | Available | Migrate to user authentication options |
For more information, refer to the user guides located on the left-side navigation or see the API reference documentation.