Struts 2.3.20 appears to have caused a regression that prevents exceptions thrown from convention-plugin actions from reaching ExceptionMappingInterceptor. This breaks exception handling when using the convention-plugin.
- Generate a project struts2-archetype-convention archetype using 2.3.20
- Throw exception in the action. With 2.3.20, a blank page is shown.
- Change to 18.104.22.168 and you will get the standard struts2 error page.
The breaking change appears to have been made in
WW-4331. This causes error interceptor code to break (showing a blank page when exceptions are thrown) as DefaultActionInvocation does not catch an exception from the default UnknownHandler implementation execution, which would previously re-throw the original exception back up for the interceptors to catch.
We've created our own UnknownHandler implementation that just throws a new NoSuchMethodException, allowing DefaultActionInvocation to re-throw the original exception so that our error interceptor can again catch it.