Can't follow property annotated with #DBRef(lazy = true) -SDR - spring-data-mongodb

Question

I might be missing something trivial or is it a bug that I could able to follow any property annotated with #DBRef(lazy = true) for my entity objects using Spring Data Rest. I see following exception when I access the property annotated with above annotation.
{
"cause": null,
"message": "Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable"
}
Environment:
Java - 7
Spring Data Rest - 2.1.1.RELEASE
Spring Data Mongo - 1.5.0.RELEASE
Tomcat - 7.x
Update 1:
Entity class:
#Document(collection = "people")
public class Employee {
#Id
private String id;
#DBRef(lazy = true)
private Employee manager;
.... truncated getters/setters
}
Here is the stacktrace
13:57:47.092 [http-bio-8080-exec-4] ERROR o.s.d.r.w.AbstractRepositoryRestController - Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable
java.lang.IllegalArgumentException: Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable
at org.springframework.util.Assert.isInstanceOf(Assert.java:337) ~[spring-core-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.data.rest.webmvc.support.RepositoryEntityLinks.linkToSingleResource(RepositoryEntityLinks.java:147) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.getSelfLinkFor(PersistentEntityResourceAssembler.java:88) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.toResource(PersistentEntityResourceAssembler.java:64) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController$1.apply(RepositoryPropertyReferenceController.java:141) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController$1.apply(RepositoryPropertyReferenceController.java:110) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController.doWithReferencedProperty(RepositoryPropertyReferenceController.java:463) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at org.springframework.data.rest.webmvc.RepositoryPropertyReferenceController.followPropertyReference(RepositoryPropertyReferenceController.java:148) ~[spring-data-rest-webmvc-2.1.0.RELEASE.jar:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_55]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_55]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_55]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_55]
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215) ~[spring-web-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132) ~[spring-web-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:685) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:919) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:851) ~[spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953) [spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:844) [spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) [servlet-api.jar:na]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829) [spring-webmvc-3.2.9.RELEASE.jar:3.2.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) [servlet-api.jar:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) [catalina.jar:7.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.50]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat7-websocket.jar:7.0.50]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) [catalina.jar:7.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.50]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) [catalina.jar:7.0.50]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) [catalina.jar:7.0.50]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:7.0.50]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) [catalina.jar:7.0.50]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) [catalina.jar:7.0.50]
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) [catalina.jar:7.0.50]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) [catalina.jar:7.0.50]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409) [catalina.jar:7.0.50]
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044) [tomcat-coyote.jar:7.0.50]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607) [tomcat-coyote.jar:7.0.50]
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315) [tomcat-coyote.jar:7.0.50]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_55]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_55]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_55]
Update 2:
Repository
#RestResource(rel = "employees", path = "employees")
public interface EmployeeRepository extends
PagingAndSortingRepository<Employee, String> {
}
WebConfiguration
public class WebApplicationInitializer extends
AbstractAnnotationConfigDispatcherServletInitializer {
public static String CURIE_NAMESPACE = "reference";
#Override
protected Class<?>[] getRootConfigClasses() {
return new Class<?>[] { ApplicationConfig.class };
}
#Override
protected Class<?>[] getServletConfigClasses() {
return new Class<?>[] { WebConfiguration.class };
}
#Override
protected String[] getServletMappings() {
return new String[] { "/api/*" };
}
#Configuration
#Import({ RespositoryConfig.class })
#ComponentScan(excludeFilters = #Filter({ Service.class,
Configuration.class }))
public static class WebConfiguration extends DelegatingWebMvcConfiguration {
#Override
protected void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new CorsInterceptor());
super.addInterceptors(registry);
}
}
#Configuration
public static class RespositoryConfig extends
RepositoryRestMvcConfiguration {
#Override
public RequestMappingHandlerMapping repositoryExporterHandlerMapping() {
RequestMappingHandlerMapping mapping = super
.repositoryExporterHandlerMapping();
mapping.setInterceptors(new Object[] { new CorsInterceptor() });
return mapping;
}
#Override
protected void configureJacksonObjectMapper(ObjectMapper objectMapper) {
objectMapper.setSerializationInclusion(Include.NON_NULL);
objectMapper.configure(
DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
}
#Override
protected void configureRepositoryRestConfiguration(
RepositoryRestConfiguration config) {
config.exposeIdsFor(App.class, BusinessUnit.class, City.class,
Country.class, Employee.class, EmployeeTalentProfile.class,
Feed.class, Goc.class, ManagedGeography.class,
ManagedSegment.class);
}
}
}
Request : http://localhost:8080/reference/api/employees/1010065136/manager
Update 3:
Line 462 of RepositoryPropertyReferenceControllers BeanWrapper.getProperty(prop) is returning default object. Digging further into BeanWrapper code line 125 obj = ReflectionUtils.getField(field, bean) returns LazyLoadingProxy. No call to database is made to populate the object.