spring content negotiating force Mime-type in error case - spring

Question

I ve got a spring service generating a pdf, if you call that service in the browser with .pdf path extension everything is working fine in success case.
However, in error case I would like to return a json error response as for all my other services.
Unfortuently, spring (Version 4.1.4) throws an exception org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
Even if I add an accept-header stating that pdf or json might be ok.
I performed following tests:
1. Request Call myService/doc.pdf with standard browser accept header
Result: Exception
2. Request Call myService/doc.pdf with specific accept header application/pdf; application/json
Result: Exception
3. Request Call myService/doc with standard browser accept header
json is returned succesfully in case of error
4. Request Call myService/doc with accept header application/pdf;application/json
json is returned succesfully in case of error
It seems to me that in case path extension is used by Spring to determine response mime-types, ONLY that Mime Type is allowed in response. However, I think it does not make any sense, to return a pdf document in case of error.
Does anybody know if I may overrule content negotiation in that case in my exception handler. Saying, well I know, that mime-type pdf is requested in url path extension, however, I Must return mime-type json.
Thanks a lot for your support in advance.
--
Volker
My content negotiation config:
<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
<property name="favorPathExtension" value="true" />
<property name="favorParameter" value="false" />
<property name="defaultContentType" value="application/json"/>
<property name="mediaTypes" >
<value>
json=application/json
xml=application/xml
</value>
</property>
</bean>
My ErrorHandler:
#ExceptionHandler(MyControlException.class)
#ResponseBody
public ResponseEntity<ErrorModel> handleMyExceptions(final MyControlException ex, final HttpServletRequest request,
final HttpServletResponse res) {
ResponseEntity<ErrorModel> response;
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
response = new ResponseEntity<ErrorModel>(ex.getError(), headers, HttpStatus.valueOf(ex.getError().getErrorCode()));
return response;
}
Exception Stack Trace:
o.s.w.s.m.m.a.ExceptionHandlerExceptionResolver - Failed to invoke #ExceptionHandler method: public org.springframework.http.ResponseEntity<com.myapp.apps2Control.common.model.ErrorModel> com.myapp.apps2Control.rest.controller.BaseApps2MceController.handleMyExceptions(com.myapp.apps2Control.common.MyControlException,javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:134) ~[spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:144) ~[spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71) ~[spring-web-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126) ~[spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver.doResolveHandlerMethodException(ExceptionHandlerExceptionResolver.java:362) ~[spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.handler.AbstractHandlerMethodExceptionResolver.doResolveException(AbstractHandlerMethodExceptionResolver.java:60) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:138) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1167) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1004) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:955) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [servlet-api.jar:na]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) [spring-webmvc-4.1.4.RELEASE.jar:4.1.4.RELEASE]