Spring weirdness

// AI.java
public interface AI
{

    String getName();
}

// A.java
@Service
public class A implements AI
{

    @Override
    public String getName()
    {
        return "a";
    }
}

// AO.java
@Service
public class AO implements AI
{
    final String name;

    public AOne(String name)
    {
        this.name = name;
    }

    public AOne()
    {
        this("DEFAULT");
    }

    @Override
    public String getName()
    {
        return name;
    }
}

// B.java
@Service
public class B
{

    @Autowired
    private AI a;

    @PostConstruct
    public void init()
    {
        System.out.println("a is: " + a.getName());
    }
}

// you will always get "a is: a" although it should be a duplicate bean definition error
// tested with Spring v1.4.2.RELEASE