Mocked repository returns null

I'm using springMVC and I would like to test my services but my @Mock repository is not working, so I will never get my user because my repository is null, how can I fix this problem? am I doing something wrong in my annotations?

Repository Interface:

package br.com.api.model.data;

import br.com.api.model.resources.User;

import java.util.List;

public interface UserDao {
    User findByLoginAndPassword(String login, String password);
    List<User> listAll();
}

Repository Implementation:

package br.com.api.model.repository;
import br.com.api.model.data.UserDao;
import br.com.api.model.resources.User;
import org.springframework.stereotype.Repository;

import java.util.ArrayList;
import java.util.List;


@Repository
public class UserRepository implements UserDao {

    public User findByLoginAndPassword(String login, String password) {
        System.out.println("lets find:");
        User userMatch = new User();
        List<User> users = usersMockup();

        for (User user : users) {
            if(user.getLogin().equals(login)
                    && user.getPassword().equals(password)){
                userMatch = user;
            }
        }

        return userMatch;
    }

    public List<User> listAll() {
        List<User> users = usersMockup();

        return users;
    }


    private List<User> usersMockup(){
        List<User> users = new ArrayList<User>();

        User first = new User();
        first.setLogin("first");
        first.setPassword("teste");

        User scnd = new User();
        scnd.setLogin("second");
        scnd.setPassword("teste");

        users.add(first);
        users.add(scnd);

        return users;
    }
}

This is my Service:

package br.com.api.model.services;


import br.com.api.model.data.UserDao;
import br.com.api.model.resources.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService {

    @Autowired
    private UserDao userRepository;

    public User findUser(String login, String password) {
        User userMatch;
        userMatch = userRepository.findByLoginAndPassword(login, password);

        return  userMatch;
    }
}

Here is my Test:

package br.com.api.model.services;


import br.com.api.model.repository.UserRepository;
import br.com.api.model.resources.User;
import org.junit.runner.RunWith;
import org.mockito.MockitoAnnotations;
import org.mockito.Mock;
import org.junit.Before;
import org.junit.Test;
import org.mockito.InjectMocks;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import static org.mockito.Mockito.when;

@RunWith(SpringJUnit4ClassRunner.class)
public class UserServiceTest {

    @Mock
    UserDao userRepository;

    @InjectMocks
    UserService userService;

    @Before
    public void setUp(){
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void findUser(){

        User user;
        user = userService.findUser("first", "teste");

        assertNotNull(user.getLogin());

    }

}