Spring-MVC does not call repository method - spring

Question

I am fairly new, and trying to make a query on my local database but the code throws a NullPointerException exception.
It is weird as it looks like it never calls the selected method of repository called findNamesByCat(String cat). It does not show the output of System.err.println("in repository"); that is located in this method.
Just after following line I called a method of another service and that works!!
List<Name> Names = myService.findNamesByCat(cat);
Error
Mar 18, 2015 1:29:07 PM
org.apache.catalina.core.StandardWrapperValve invoke
... threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.myproject.web.MyController.showCategoryNames(MyController.java:41)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Code
#Controller
public class myController {
#Autowired
private MyService myService;
#RequestMapping(value = "/{cat}", method = RequestMethod.GET)
public String showCategoryNames(#PathVariable String cat, Model model) {
System.err.println("in web"); //shows this
List<Name> Names = myService.findNamesByCat(cat);
System.err.println(Names.size()); //this is line 41
model.addAttribute("Names", Names);
model.addAttribute("cat", cat);
return "cat";
}
#Service
public class MyServiceImpl implements MyService {
#Autowired
private NameRepository nameRepository;
#Override
#Transactional(readOnly = true)
public List<Name> findListOfNamesByCat(String cat) {
System.err.println("in service"); //does not show this
return nameRepository.findNamesByCat(cat);
}
}
#Repository
public class NameRepositoryImp implements NameRepository {
#Autowired
SessionFactory sessionFactory;
#Override
public List<Name> findNamesByCat(String cat){
System.err.println("in repository"); //does not show this
try {
Criteria crit = sessionFactory.getCurrentSession().createCriteria(
Name.class);
crit.add(Restrictions.eq("category", cat));
return crit.list();
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
Servlet
<context:annotation-config />
<mvc:annotation-driven />
<mvc:resources mapping="/resources/**" location="/resources/" />
<context:component-scan base-package="com.myproject" />
UPDATE
I made following changes as well but it does not work yet.
#Controller
public class myController {
#Autowired
#Qualifier("repositoryService")
private MyService myService;
#Service(value = "repositoryService")
public class MyServiceImpl implements MyService {
#Autowired
#Qualifier("repositoryMain")
private NameRepository nameRepository;
#Repository(value = "repositoryMain")
public class NameRepositoryImpl implements NameRepository {
#Autowired
SessionFactory sessionFactory;

Answer 1

You defined #PathVariable String cat, but didn't mark it correctly in #RequestMapping, add {} for PathVariable "cat", like this:
#RequestMapping(value = "/{cat}", method = RequestMethod.GET)

Answer 2

The issue was that, for some reasons the body of the methods that I was calling were empty and the correct bodies where replaced by body of other methods. After replacing the bodies and cleaning the project it started working. Thank you for your attempt to help and apologies for the confusion.