MyExceptionMapper.java

package org.jboss.seam.compat.jaxrs.provider;

import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.SecurityContext;
import javax.ws.rs.ext.ExceptionMapper;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.Providers;

@Provider
@ApplicationScoped
public class MyExceptionMapper implements ExceptionMapper<NullPointerException> {
    @Context
    private SecurityContext securityContext;
    @Context
    private Providers providers;
    @Context
    private ServletConfig servletConfig;
    @Context
    private ServletContext servletContext;
    @Inject
    private Foo cdiFieldInjection;

    @Override
    public Response toResponse(NullPointerException exception) {
        StringBuilder builder = new StringBuilder();
        builder.append("SecurityContext:" + (securityContext != null));
        builder.append(",Providers:" + (providers != null));
        builder.append(",ServletConfig:" + (servletConfig != null));
        builder.append(",ServletContext:" + (servletContext != null));
        builder.append(",CDI field injection:" + (cdiFieldInjection != null));
        return Response.status(200).entity(builder.toString()).type(MediaType.TEXT_HTML).build();
    }
}