@Qualifier for Qualifying bean

Using @Primary annotation you can specify the priority for the bean but when there are multiple then you still have the ambiguity then you can get the qualifying bean using the @Qualifier annotation.

Using @Qualifier annotation is you can work with qualifiers.
It can be used with the @Autowired or @Inject , to specify at the point of injection which
bean you wish to be injected.

If you want Mango bean is injected into setIceCream(IceCream iceCream):
@Autowired
@Qualifier("mango")
public void setIceCream(IceCream iceCream) {
   this.iceCream= iceCream;
}

The parameter given in the @Qualifier is the ID of the bean.
Bean of all the @Component annotated classes will be  create with ID as a uncapitalized class name.
There  @Qualifier("mango") refers to the Mango class.

But here if you refactor the Mango class then it can create problem here.
So, in that case you can specify the @Qualifier with the @Bean annotation.

@Autowired
@Qualifier("myMango")
public void setIceCream(IceCream iceCream) {
   this.iceCream= iceCream;
}

In the mango class you can have this 
@Bean
@Qualifier("myMango")
public Icecream iceCream() {
    return new Mango();
}