Status codes returned by the IBM BPM REST APIs

If an error occurs during the processing of a REST request, the REST methods return an appropriate HTTP status code to the calling client.

The following status codes are returned.

Table 1.
Status code	Explanation
Successful completion
`200 OK`	The request completed successfully.
`201 Created`	The request completed successfully; a new resource was created.
`204 No Content`	The request completed successfully, but content is not available
Expected error situations
`400 Bad Request`	The REST request contains parameters that are not valid, or they are missing.
`401 Unauthorized`	The caller is not authorized to perform the request.
`403 Forbidden`	The caller is not authorized to complete the request.
`404 Not Found`	The requested resource does not exist.
`406 Not Acceptable`	An unsupported content type or content encoding was requested.
`409 Conflict`	A conflict exists with the current state of the resource. The requested action cannot be performed on the resource in its current state.
`415 Unsupported Media Type`	The request contains an unknown content type or content encoding.
Unexpected error
`500 Internal Server Error`	A problem has occurred; additional information is provided in the stack trace.
`501 Not Implemented`	The request is not supported by the IBM® Business Process Manager REST API.
`503 Service Unavailable`	Federated requests could not be delivered to all of the federation targets.
`504 Gateway Timeout`	A federated response is not complete because responses are missing from some federation targets.

For BPD resources, error responses omit the server-side exception details because of security considerations. To include these details in the error response, set the associated property in the 100Custom.xml file for the process server:

<server-stacktrace-enabled>true</server-stacktrace-enabled>