App Engine Documentation PHP Standard Environment Documentation API Documentation \google\appengine\api\taskqueue\TaskAlreadyExistsException Thrown when adding a task, but a task with the same name already exists in the queue. Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated February 22, 2017.