Validation Field Errors
A validationfieldError is generated during a JSR303 validation. Output includes fieldName, code, and message. It’s mapped to the HTTP 400 status code.
Operation Errors
This error is generated from a variety of error conditions, but it generally refers to an issue with the service (as opposed to the client or user). Every object in anoperationErrors array will contain a code and message, and these are designed to be explicit enough to clarify the reason for the error.

