Question

i have a problem with spring autowire feature which found two beans with the same type, but in fact i only have one bean and the interface that this bean is implementing.

In applicationContext.xml i have these lines:

<context:component-scan base-package="xxx.vs.services"/>
<context:component-scan base-package="xxx.vs.dao"/>  
<context:annotation-config/> 

<bean id="intermedDao" class="xxx.vs.dao.yyy.IntermedDaoImpl" />

and :

package xxx.vs.dao.abs.yyy;    
public interface IntermedDao extends GenericDao<Intermed> {
    // methods here
}

---

package xxx.vs.dao.yyy;    
import org.springframework.stereotype.Repository;
@Repository
public class IntermedDaoImpl extends GenericInboundDaoImpl<Intermed> implements IntermedDao {
    // methods here
}

---

package xxx.vs.services.yyy;
@Service
@Transactional
public class IntermedServiceImpl implements IntermedService {

    @Autowired
    IntermedDao dao;

    public IntermedDao getDao() {
        return dao;
    }

    public void setDao(IntermedDao dao) {
        this.dao = dao;
    }    
}

with this config i get:

java.lang.Exception: java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: 
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'intermedServiceImpl': 
Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: 
Could not autowire field: xxx.vs.dao.abs.yyy.IntermedDao xxx.vs.services.yyy.IntermedServiceImpl.dao; nested exception is 
org.springframework.beans.factory.NoSuchBeanDefinitionException:No unique bean of type [xxx.vs.dao.abs.yyy.AgentDao] is defined: expected single matching bean but found 2: [intermedDaoImpl, intermedDao]  

does this happens because i scan the packages that contains the interfaces that my DAO`s classes are implementing ?

Answer 1

This is happening because you’ve both explicitly declared a bean:

<bean id="intermedDao" class="xxx.vs.dao.yyy.IntermedDaoImpl" />

as well as declaring a @Repository to be picked up by component scanning:

@Repository
public class IntermedDaoImpl

You need to do one or the other, not both. I suggest deleting the <bean>.

Note that the error message:

expected single matching bean but found 2: [intermedDaoImpl, intermedDao]

Mentions the conflicting beans. The first one is your @Repository, where the name of the bean is auto-generated from the classname; the second one is your <bean>.