I am attempting to use Junit, mockito and PowerMock to create a unit test

I am attempting to use Junit, mockito and PowerMock to create a unit test

My problem is that one of the classes which i am attempting to mock is returning a null object

This is my code

    @RunWith(PowerMockRunner.class)
@PrepareForTest(ClientBuilder.class)
public class SolrPopulateApplicationTest {

   @Mock
   ClientConfig clientConfig;

   @Mock
   Client client;

   @Mock
   Response response;

   @Mock
   JerseyClient jerseyClient;

   @Mock (answer = Answers.RETURNS_DEEP_STUBS)
   JerseyWebTarget jerseyWebTarget;

   @InjectMocks
   @Autowired
   SolrPopulateApplication solrPopulateApplication;

   @Test
   public void indexTest(){

       PowerMockito.mockStatic(ClientBuilder.class);

       ClientBuilder cli = Mockito.mock(ClientBuilder.class);

    when(ClientBuilder.newClient(Matchers.any())).thenReturn(client);

       when(jerseyClient.target(Matchers.anyString())).thenReturn(jerseyWebTarget);

       when(jerseyWebTarget.path(Matchers.anyString())
               .queryParam(Matchers.anyString(),Matchers.anyString())
       .request(Matchers.anyString())
               .header(Matchers.anyString(),Matchers.anyString())
       .post(Matchers.any())).thenReturn(response);

       boolean var = solrPopulateApplication.index("test","test");

   }
}

When a debug breakpoint is placed after all the mocks should have been setup i get the following

    client = {Client$$EnhancerByMockitoWithCGLIB$$7f4c6946@1705} "client"
response = {Response$$EnhancerByMockitoWithCGLIB$$b85fdf42@1704} "response"
jerseyWebTarget = {JerseyWebTarget$$EnhancerByMockitoWithCGLIB$$7d7091b9@1703} "null"
solrPopulateApplication = {SolrPopulateApplication@1702} 
jerseyClient = {JerseyClient$$EnhancerByMockitoWithCGLIB$$6437ba91@1701} "jerseyClient"
cli = {ClientBuilder$$EnhancerByMockitoWithCGLIB$$20196b6d@1700} "Mock for ClientBuilder, hashCode: 2080643905"
this = {SolrPopulateApplicationTest@1695}

as you can see the jerseyWebClient is a NULL and this is causing a nullpointerexception when i try to run the test.

I have tried removing (answer = Answers.RETURNS_DEEP_STUBS) from the @mock statement and this makes no difference.

The method being tested actually calls a interface which implements the JerseyWebTarget class. I have made sure I am trying to mock the right class by putting a debugger in the JerseyWebTarget class to make sure its stopping on the method which is being called via the interface.

can anyone tell me why this is happening and how to fix it.