406 error on Spring MVC integration test, while the service works fine in browser - spring

Question

I have a Spring 4 MVC web application. I am doing the Integration Test for my REST Services. The services are working fine from invoking through browser rest-clients and jquery/restangular UI as well. However, when I run my Integration Test, I am getting the error Expected :200 Actual :406.
This issue comes only when Spring convert the Object to json. I tried manual conversion by ObjectMapper and returned the result. In this case, the test started working.
Here are my files:
Controller:
#RequestMapping(value="/permissions", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<Object> getPermissions() throws Exception {
return new ResponseEntity<Object>(getPermissions(), HttpStatus.OK);
}
Integration Test:
#RunWith(SpringJUnit4ClassRunner.class)
#WebAppConfiguration
#ContextConfiguration({"classpath*:rest-config.xml", "classpath:domain-config.xml"})
public class ITController {
#Autowired
private WebApplicationContext context;
private MockMvc mockMvc;
#Before
public void setup() {
this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context).build();
}
#Test
public void getPermissions() throws Exception {
MvcResult result = this.mockMvc.perform(get("/permissions/4")
.accept("application/json"))
.andExpect(status().isOk())
.andExpect(content().contentType("application/json")).andReturn();
Permission p = new GsonBuilder().create().fromJson(result.getResponse().getContentAsString(), Permission.class);
Assert.assertNotNull(p);
}
}
If I add the below code to the controller, then the test start working.
ObjectMapper mapper = new ObjectMapper();
String stringVal = mapper.writeValueAsString(permission);
Part of my spring config file:
<mvc:annotation-driven/>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="order" value="1"/>
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes" value="application/json"/>
</bean>
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes" value="text/plain;charset=UTF-8"/>
</bean>
</list>
</property>
</bean>
I am using jackson version 2.2.1 in my application.
DEBUG Log
2014-07-14 14:41:37 DEBUG EntityPrinter:121 - com.myapp.entity.Permission{isActive=true, description=permission, id=4, Name=mypermission}
2014-07-14 14:41:37 DEBUG JdbcTransaction:113 - committed JDBC Connection
2014-07-14 14:41:37 DEBUG JdbcTransaction:126 - re-enabling autocommit
2014-07-14 14:41:37 DEBUG LogicalConnectionImpl:314 - Releasing JDBC connection
2014-07-14 14:41:37 DEBUG LogicalConnectionImpl:332 - Released JDBC connection
2014-07-14 14:41:37 DEBUG ConnectionProxyHandler:219 - HHH000163: Logical connection releasing its physical connection