Jersey Exception mappers not working when jackson deserialization fails

I tested it with an exception mapper like below:

import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.ext.ExceptionMapper;
import javax.ws.rs.ext.Provider;

import com.fasterxml.jackson.core.JsonProcessingException;

@Provider
public class JsonProcessingExceptionMapper implements ExceptionMapper<JsonProcessingException>{

        public static class Error {
            public String key;
            public String message;
        }

        @Override
        public Response toResponse(JsonProcessingException exception) {
            Error error = new Error();
            error.key = "bad-json";
            error.message = exception.getMessage();
            return Response.status(Status.BAD_REQUEST).entity(error).build();
        }
}

and it worked.

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Update: changed JsonParseException to JsonProcessingException (more general)

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Update2: In order to avoid registering the unwanted mappers replace

register(org.glassfish.jersey.jackson.JacksonFeature.class);

with

register(com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider.class);

Look at the source code of JacksonFeature and you'll understand what's happening.

Starting with Jersey 2.26 (1, 2) it should be enough to annotate the custom exception mapper with a sufficiently high Priority (high here meaning a low, strictly positive number). To override the “default” mappers provided by org.glassfish.jersey.media:jersey-media-json-jackson (to register(JacksonFeature.class)) we only provide these two custom mappers:

@Provider
@Priority(1)
public class JsonMappingExceptionMapper implements ExceptionMapper<JsonMappingException> {
  /* ... */
}

@Provider
@Priority(1)
public class JsonParseExceptionMapper implements ExceptionMapper<JsonParseException> {
  /* ... */
}

Unfortunately JAX-RS 2 Spec disregards priorities and only states:

When choosing an exception mapping provider to map an exception, an implementation MUST use the provider whose generic type is the nearest superclass of the exception.

Not registering JacksonFeature.class and registering JacksonJaxbJsonProvider.class instead as mentioned in another answer did not lead to consistent results.

I used "jackson-jaxrs-json-provider 2.8.8" and JAX-RS 2.0

Application class - you needs to register your ExceptionMapper implementation class:

@ApplicationPath("pathApplication")
public class ApplicationConfiguration extends Application{


   @Override
   public Set<Class<?>> getClasses() {

      Set<Class<?>> resources = new HashSet<>();
      resources.add(YourJAXRSClass.class);
      resources.add(JsonJacksonEM.class); //ExceptionMapper class implementation
      //others resources that you need...
      return resources; 

   }


}

ExceptionMapper class implementation:

@Provider
public class JsonJacksonEM implements ExceptionMapper<JsonParseException>{


   @Override
   public Response toResponse(JsonParseException exception) {
      //you can return a Response in the way that you want!
      return Response.ok(new YourObject()).build();
   }


}

I had the same problem, and the previous answer led me to the solution, but was not forking for me current Jersey (2.22). At first, I needed to use the org.glassfish.jersey.spi.ExtendedExceptionMapper like described in https://jersey.java.net/documentation/latest/representations.html.

Furthermore, Jersey is checking for an exception mapper, which is as close as possible to the thrown exception (from org.glassfish.jersey.internal.ExceptionMapperFactory):

for (final ExceptionMapperType mapperType : exceptionMapperTypes) {
        final int d = distance(type, mapperType.exceptionType);
        if (d >= 0 && d <= minDistance) {
            final ExceptionMapper<T> candidate = mapperType.mapper.getService();

            if (isPreferredCandidate(exceptionInstance, candidate, d == minDistance)) {
                mapper = candidate;
                minDistance = d;
                if (d == 0) {
                    // slight optimization: if the distance is 0, it is already the best case, so we can exit
                    return mapper;
                }
            }
        }
    }

Therefore I needed to map exactly the exception and not a more general exception.

In the end, my provider looks as follows:

@Provider
public final class JsonParseExceptionExceptionHandler implements ExtendedExceptionMapper<JsonParseException> {
    @Override
    public Response toResponse(final JsonParseException exception) {
        exception.printStackTrace();
        return Response.status(Response.Status.BAD_REQUEST).entity("JSON nicht in korrektem Format.").build();
    }

    @Override
    public boolean isMappable(final JsonParseException arg0) {
        return true;
    }
}