Under PROJECT/resources create a file called error.template. Inside this file, place the formatted error template you want to return when a custom exception is thrown. If no custom template is given, the following default template will be used:

<error>
%s
</error>```

Annotate the custom exception class with `@Exception(*httpStatus*, *contentType*)`.
The defaults are
`httpStatus = HttpStatus.INTERNAL_SERVER_ERROR`
`contentType = MediaType.APPLICATION_XML_VALUE`.
The custom message is taken from the custom annotation class itself, so any parameters you'd like to insert need to be handled there.

Make sure to add `com.raychatter.common.annotation.AnnotationHandler` as a bean in your XML.
And that's it!