ExceptionHandler doesn't work with Throwable

Question

Ours is a Spring MVC based REST application. I am trying to use ExceptionHandler annotation to handle all errors and exceptions.

I have

    @ExceptionHandler(Throwable.class)
    public @ResponseBody String handleErrors() {
        return "error";
    }

This works whenever there is an exception thrown and it doesn't work for any errors.

I am using Spring 4.0. Is there any work-around?

Answer 1

Contrary to what the ExceptionHandler#value() attribute indicates

Class<? extends Throwable>[] value() default {};

and @ExceptionHandler is only meant to handle Exception and its sub types.

Spring uses ExceptionHandlerExceptionResolver to resolve your annotated handlers, using the following method

doResolveHandlerMethodException(HttpServletRequest request,
        HttpServletResponse response, HandlerMethod handlerMethod, Exception exception) 

which as you can see only accepts an Exception.

You cannot handle Throwable or Error types with @ExceptionHandler with this configuration.

I would tell you to provide your own HandlerExceptionResolver implementation which does handle Throwable instances, but you'd need to provide your own DispatcherServlet (and most of the MVC stack) yourself since DispatcherServlet does not catch Throwable instances at any place where you could make any significant difference.

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Update:

Since 4.3, Spring MVC wraps a thrown Throwable value in a NestedServletException instance and exposes that to the ExceptionHandlerExceptionResolver.