SpringMVC- Mockito- Junit - NullPointerException when service class method is called from controller class

Question

I am writing a web-application, by using spring MVC . I have made a service class to map things to and from the database using UI.

My problem is I am new to junit and mockito when i am trying to write unit tests on Controller class, it always returns a NullPointerException. It is really annoying since I am unable to find the answer, so I hope you guys can help me out. Below I have posted my code.

My Controller class method on /update return success

@RequestMapping(value = "/update", method = RequestMethod.POST)
    public String updateFormData(@ModelAttribute CRDetails certGuide,
            ModelMap model) { 
        crService.updateCertification(certGuide);
        return "success";   
}

My Service class method updates mongodb with modified data

public void updateCertification(CRDetails certGuide) {      String userTypeSubmitted = certGuide.getCertGuidelines().getUserType();         System.out.println("updated by " + userTypeSubmitted);      Update update = new Update();       Query query = new Query(Criteria.where("cr").is("CR1"));

        CRDetails details = certMongoTemplate.findOne(query, CRDetails.class,
                COLLECTION_NAME);       CertificateGuidelines newCertGuide = new CertificateGuidelines();

        if (details != null) {          newCertGuide.setCertG(certGuide.getCertGuidelines().getCertG());            if (userTypeSubmitted.equals("Certification Team")
                    && userTypeSubmitted != "") {
                newCertGuide.setStatus("Pending with Document Developer");          } else {
                newCertGuide.setStatus("Pending with Certification Team");          }           newCertGuide.setHistoryCount(++count);

            // converting it into mongo document.           MongoConverter converter = certMongoTemplate.getConverter();            DBObject newRec = (DBObject) converter
                    .convertToMongoType(newCertGuide);          update.set("certGuidelines", newRec);       }

        System.out.println("new cert guide " + newCertGuide.getCertG() + " "
                + newCertGuide.getStatus() + " "
                + newCertGuide.getHistoryCount() + " "
                + newCertGuide.getUserType());
                certMongoTemplate.updateFirst(query, update, CRDetails.class); }

My controllerTest class which return NullPointerException.

import static org.junit.Assert.assertEquals;

import org.junit.Before; 
import org.junit.Test; 
import org.mockito.InjectMocks; 
import org.mockito.Mock;  
import org.mockito.Mockito; 
import org.springframework.test.web.server.MockMvc; 
import org.springframework.ui.ModelMap; 
import org.springframework.web.servlet.View;

import com.cerner.docworks.controller.CRController; 
import com.cerner.docworks.domain.CRDetails; 
import com.cerner.docworks.service.CRService;


public class CRControllerTest  {

    /*@Mock     private CRService service;*/
    @Mock   View mockView;

   @InjectMocks      
   private CRController crController;

    private MockMvc mockMvc;

     @Before     public void setup() {
             }

    @Test   public void testUpdate() throws Exception {          //     CRService service = Mockito.mock(CRService.class);      CRService crService = Mockito.spy(new CRService());         ModelMap model = Mockito.mock(ModelMap.class);      CRDetails certGuide = Mockito.spy(new CRDetails());
                CRController controller = new CRController();

                 //     Mockito.when(service.updateCertification(certGuide)); //        Mockito.when(model.addAttribute(Matchers.eq("certGuide"),any(String.class))).thenReturn(null); //       Mockito.doThrow(new RuntimeException()).when(crService).updateCertification(certGuide);         Mockito.doNothing().when(crService).updateCertification(certGuide);         Mockito.mockingDetails(certGuide); //       Mockito.doCallRealMethod().when(crService).updateCertification(certGuide); //       Mockito.(crService)).updateCertification(certGuide);;       String fileName = controller.updateFormData(certGuide, model);
                System.out.println(fileName); //        Mockito.verify(controller).updateFormData(certGuide, model);        assertEquals("success", fileName);  } }

Trace:

java.lang.NullPointerException at com.cerner.docworks.controller.CRController.updateFormData(CRController.java:81) at com.cerner.docworks.controller.test.CRControllerTest.testUpdate(CRControllerTest.java:62) 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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

FYI, CRDetails is a pojo class with

private String id;
    private String cr;
    private String desc;
    private CertificateGuidelines certGuidelines;
    private Date dueDate;
    //private String userType;
    private String solutionName;

FYI, When i am debugging the code, i found mock is setting objects to null If i do set details manually, test case pass but, i want to use mockito.

Thanks in advance for ur help.

The better approach is to use constructor injection on your controller. You can use Mockito mocks easily without the need for reflection hacks. — chrylis -cautiouslyoptimistic-

Jonathan Jonathan · Accepted Answer · 2015-02-19T17:07:07

You need to run the test with the MockitoJUnitRunner, e.g.:

@RunWith(MockitoJUnitRunner.class)
public class CRControllerTest {
     // ...

This allows @InjectMocks and @Mock to work properly. I.e. mockView will be created as a mock of View and crController will be created with relevant @Mock-annotated fields.

You can refer to the documentation to see how the mocks are injected.

SpringMVC- Mockito- Junit - NullPointerException when service class method is called from controller class

1 Answers