Difference between @Qualifier and @Resource

Question

I don’t see any difference between two ways, @Qualifier is always used with @Autowired.

@Autowired
@Qualifier(\"alpha\")

Answer 1

I was facing some issues with @Autowired and then started using @Qualifier and I was finally able to find out the when to use @Autowired with @Qualifier when multiple beans of same type are defined.

Suppose you define 2 beans of same type but different values :

Then if you just are trying to use @Autowire, then you have to use the same variable name as of the bean name else it will give error as multiple types found.

@Autowired
AppContext appContext;

For the above use case you have to use Qualifier.

@Autowired
@Qualifier("appContext1")
AppContext appContext;

Instead, if you use the variable name same as bean name, you can eliminate the use of @Qualifier.

@Autowired
AppContext appContext1;

I was always using the variable name same as bean name, but accidentally had some other variable name and faced this issue.

Let me know if there are any doubts.