License request error handling
If an error occurs during request parsing, a HandlerParsingException occurs. This exception includes error information that is returned to the client. If you need to retrieve the error information, you need to call HandlerParsingException.getErrorData() . If an error occurs during the generation of a license because of DRM policy requirements that have not been satisfied, a PolicyEvaluationException occurs. This exception also includes ErrorData to be returned to the client.
See the API documentation for LicenseRequestMessage.generateLicense() for details on how DRM policies are evaluated during license generation.