Spring Best practice for Dependency Injection

I have some confusion about DI in spring

public interface A{
    void methodA();
}
public class AImpl implements A{
    public void methodA(){
          // todo something
    }
}

public interface B{
    void methodB();
}
public class BImpl implements B{
     public void methodB(){
       //todo somethong
     }
}

I have two interface A and B and 2 class implements it. So, I have 2 Class that implement interface C, it depend on Interface A and B

This is case 1:

public interface C{
    void methodC();
}

public class CAutowired implements C{
    @Autowired
    private A a;
    @Autowired
    private B b;

    public void methodC(){
       a.methodA();
       b.methodB();
    }
}

File .xml config

  <beans>
       <bean id="classA" class="com.example.AImpl" />
       <bean id="classB" class="com.example.BImpl" />
       <bean id="classC" class="com.example.CAutowired" />
    <beans>

In this case, i have a question: - How to Mock A and B when i write unitTest for class CAutowired

This is case 2:

public class CInitInject implements C{
    private A a;
    private B b;

    public CInitInject(A a, B b){
       this.a = a;
       this.b = b;
    }

    public void methodC(){
       a.methodA();
       b.methodB();
    }
}

File .xml config

  <beans>
       <bean id="classA" class="com.example.AImpl" />
       <bean id="classB" class="com.example.BImpl" />
       <bean id="classC" class="com.example.CInitInject">
             <constructor-arg ref="classA" />
             <constructor-arg ref="classB" />
       </bean>
    <beans>

In this case, i get DI method the same in .NET. I can Mock A and B by inject into constructor. Example:

@Mock
private A aMock;
@Mock
private B bMock;

private C c;

public void setUp(){
   c = new CInitInject(aMock, bMock);
}

@Test
public void test(){
   // todo Test somemethod
}

End of all, I have a question

1. What is best practice between case 1 and case 2?
2. How to Mock it when unit test