How to avoid handling RunTimeException in Jersey

Question

The most popular desicion for handling exceptions in rest service and return the error message to client - as i understand - is to catch WebApplicationException or MappableContainerException. But they are extending RuntimeExceprion (I don't understand why). As I know we should avoid handling RuntimeExceptions.

I need to handle such exceptions as "The entity with such name already exsists". I'm sure it is not a runtime exception.

Any other ways? I'm researching now Wrappers. May be you could excplain me the best way to solve my problem?

Answer 1

The way that I handle this is to have my own exception hierarchy, and to build a separate ExceptionMapper which handles this hierarchy. That allows me to pass back whatever information I need to (in my case a JSON-formatted response) in a standardized way.

I would still have an ExceptionMapper for WebApplicationException, otherwise the end user might receive some nasty looking responses. And if you want to be extra-safe then you can also put one in for Exception that picks up anything else you might have missed (the exceptions go to the most specific exception mapper for them, so putting one in for Exception doesn't affect them).