What Is a Qualifier Java

A qualifier is an annotation that you apply to a bean. A qualifier type is a Java annotation defined as @Target({METHOD, FIELD, PARAMETER, TYPE}) and @Retention(RUNTIME). For example, you could declare an @Informal qualifier type and apply it to another class that extends the Greeting class.

What is a spring qualifier?

We can do that via the @Qualifier annotation. For instance, we could specify that we want to use the bean returned by the johnEmployee method by using the @Qualifier annotation. It’s worth noting that if both the @Qualifier and @Primary annotations are present, then the @Qualifier annotation will have precedence.

What is the difference between @autowired and @qualifier?

The difference are that @Autowired and @Qualifier are the spring annotation while @Resource is the standard java annotation (from JSR-250) . Besides , @Resource only supports for fields and setter injection while @Autowired supports fields , setter ,constructors and multi-argument methods injection.