SpringBoot: how to inject two classes having same name - spring

Question

In my application, I have two classes having the same name, but of course in different packages.
Both classes need to be injected in the application; Unfortunately, I get the following error message:
Caused by: org.springframework.context.annotation.ConflictingBeanDefinitionException: Annotation-specified bean name 'myFeature' for bean class [org.pmesmeur.springboot.training.service.feature2.MyFeature] conflicts with existing, non-compatible bean definition of same name and class [org.pmesmeur.springboot.training.service.feature1.MyFeature]
My issue can be reproduced by the following sample:
#Component
#EnableConfigurationProperties(ServiceProperties.class)
public class MyService implements IService {
private final ServiceProperties serviceProperties;
private final IProvider provider;
private final org.pmesmeur.springboot.training.service.feature1.IMyFeature f1;
private final org.pmesmeur.springboot.training.service.feature2.IMyFeature f2;
#Autowired
public MyService(ServiceProperties serviceProperties,
IProvider provider,
org.pmesmeur.springboot.training.service.feature1.IMyFeature f1,
org.pmesmeur.springboot.training.service.feature2.IMyFeature f2) {
this.serviceProperties = serviceProperties;
this.provider = provider;
this.f1 = f1;
this.f2 = f2;
}
...
package org.pmesmeur.springboot.training.service.feature1;
public interface IMyFeature {
void print();
}
package org.pmesmeur.springboot.training.service.feature1;
import org.springframework.stereotype.Component;
#Component
public class MyFeature implements IMyFeature {
#Override
public void print() {
System.out.print("HelloWorld");
}
}
package org.pmesmeur.springboot.training.service.feature2;
public interface IMyFeature {
void print();
}
package org.pmesmeur.springboot.training.service.feature2;
import org.springframework.stereotype.Component;
#Component
public class MyFeature implements IMyFeature {
#Override
public void print() {
System.out.print("FooBar");
}
}
If I use different names for my classes MyFeature, my problem disappears!!!
I am used to work with Guice and this framework does not have this kind of problem/limitation
It seems that the spring dependencies injection framework uses only
the class-name instead of package-name + class-name in order to
select its classes.
In "real-life" I have this problem with a far-bigger project and I would strongly prefer not to have to rename my classes: can anyone help me?
One last point, I would prefer to avoid "tricks" such as using
#Qualifier(value = "ABC") when injecting my classes: in my sample,
there should be no ambiguity for finding the correct instance of
MyFeature as they do not implement the same interface

Answer 1

Simply re-implementing BeanNameGenerator adds a new problem for beans declared/instantiated by names
#Component("HelloWorld")
class MyComponent implements IComponent {
...
}
#Qualifier(value = "HelloWorld") IComponent component
I solved this issue by extending AnnotationBeanNameGenerator and redefining method buildDefaultBeanName()
static class BeanNameGeneratorIncludingPackageName extends AnnotationBeanNameGenerator {
public BeanNameGeneratorIncludingPackageName() {
}
#Override
public String buildDefaultBeanName(BeanDefinition beanDefinition, BeanDefinitionRegistry beanDefinitionRegistry) {
return beanDefinition.getBeanClassName();
}
}

Answer 2

You can assigna a value for each component e.g. #Component(value="someBean") and then inject it with #Qualifier e.g.
#Autowired
public SomeService(#Qualifier("someBean") Some s){
//....
}

Answer 3

Spring provides autowire by type and name. Your classname are same. By default spring considers only className not package. But you can override this behaviour by defining custom implementation of BeanNameGenerator interface in which you can generate name using both package and name. I am not providing code solution because i think you should explore more on this.

Answer 4

You can do something like this;
in package a
public class MyFeature implements IMyFeature {
#Override
public void print() {
System.out.print("FooBar");
}
}
in package b
public class MyFeature implements IMyFeature {
#Override
public void print() {
System.out.print("HelloWorld");
}
}
and in some config class;
#Configuration
public class Configuration {
#Bean
public a.MyFeature f1() {
return new a.MyFeature();
}
#Bean
public b.MyFeature f2() {
return new b.MyFeature();
}
}
Then you can autowire them with names f1 and f2, that are the names of their respective bean constructor methods.
You can do the similar thing with #Component("f1") &
#Component("f2")
Even though different interfaces are implemented and are in different packages, identical bean name causes this trouble, and you have to utilize some sort of custom naming to distinguish. Utilizing some custom Spring logic would be way too ugly compared to what you'd do with above solutions.