Jersey custom ExceptionMapper not called on 400 Bad Request (when validation fails) - spring

Question

I'm using Jersey with Spring for web services. For catching exceptions and formatting the response sent to the caller I have added an implementation of ExceptionMapper.
Though it is being called when I explicitly throw an exception from within the controller, but when the json field validation fails the exception mapper is not called and the response sent is **may not be null (path = checkNotification.arg0.tyres, invalidValue = null)
**
#Provider
public class GenericExceptionMapper implements ExceptionMapper<Throwable> {
#Override
public Response toResponse(Throwable ex) {
System.out.println("Exception Mapper !!!");
return Response.status(404).entity(ex.getMessage()).type("application/json").build();
}
}
<servlet>
<servlet-name>jersey-servlet</servlet-name>
<servlet-class>
org.glassfish.jersey.servlet.ServletContainer
</servlet-class>
<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>
com.help.rest.controller,
com.fasterxml.jackson.jaxrs.json
</param-value>
</init-param>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>com.help.filter.FeatureRegistration</param-value>
</init-param>
<init-param>
<param-name>jersey.config.beanValidation.enableOutputValidationErrorEntity.server</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
Jersey Version is 2.22.1
Spring Version is 4.2.4
I made it work by changing
#Provider
public class GenericExceptionMapper implements ExceptionMapper<Throwable> {
#Override
public Response toResponse(Throwable ex) {
System.out.println("Exception Mapper !!!");
return Response.status(404).entity(ex.getMessage()).type("application/json").build();
}
}
to
#Provider
public class GenericExceptionMapper implements ExceptionMapper<ConstraintViolationException> {
#Override
public Response toResponse(ConstraintViolationException ex) {
System.out.println("Exception Mapper !!!");
return Response.status(404).entity(ex.getMessage()).type("application/json").build();
}
}
Though I'm able to catch the exception I am not getting the exact class and field which failed the constraint.
Resolved
Found a Set containing all the required fields in ContraintViolationException, could be accessed using ex.getConstraintViolations()

Answer 1

made it work by changing
#Provider
public class GenericExceptionMapper implements ExceptionMapper<Throwable> {
#Override
public Response toResponse(Throwable ex) {
System.out.println("Exception Mapper !!!");
return Response.status(404).entity(ex.getMessage()).type("application/json").build();
}
}
to
#Provider
public class GenericExceptionMapper implements ExceptionMapper<ConstraintViolationException> {
#Override
public Response toResponse(ConstraintViolationException ex) {
System.out.println("Exception Mapper !!!");
return Response.status(404).entity(ex.getMessage()).type("application/json").build();
}
}
To get the exact exception details, like which field failed the constraint use ConstraintViolationException's getConstraintViolations(). This method provides a set for all the constraint violations.

Answer 2

You need to register it:
public class MyApplication extends Application {
public Set<Class<?>> getClasses() {
Set<Class<?>> s = new HashSet<Class<?>>();
s.add(HelloWorldResource.class);
/** you need to add ExceptionMapper class as well **/
s.add(GenericExceptionMapper.class)
return s;
}
}