Difference between @inject annotation and Constructor/Setter + XML config Injection?

Asked Jan 08 '16 at 14:23

Active Jan 08 '16 at 17:31

Viewed 89 times

( This is not a duplicate question, There is nothing about the @inject annotation here : Dependency injection through constructors or property setters? )

If I understand it right, in Spring for example, we define a bean in the xml file, and then we can inject it via constructor or setter, so the Spring IOC container will manage the lifecycle of that bean.

Example 1 :

class Test {

    private Bean bean;

    //constructor injectioon
    public Test(Bean bean) {
        this.bean = bean;
    }
    //setter injection
    public setBean(Bean bean) {
        this.bean = bean;
    }
}

So what is the difference between the example 1 and the following example ( and correct me please if I'm wrong about what I've said in the first paragraph :

Example 2 :

class Test {

    @inject
    private Bean bean;

    public Test() {

    }
}

Thanks in advance.

edited May 23 '17 at 11:52

Community

asked Jan 08 '16 at 14:23

Dwix

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1

They work the same. But in Spring we should use `@Autowire` instead of `@Inject` – Krzysztof Majewski Jan 08 '16 at 14:29
1

There are ways to inject a value, they do not have differences. – Andrew Tobilko Jan 08 '16 at 14:30
Thank you for your answers. – Dwix Jan 08 '16 at 14:30
@KrzysztofMajewski - Why is that? Why unnecessarily add a dependency to Spring? – DavidR Jan 08 '16 at 14:31
4

Constructor injection can fail if you have a circular dependency between two beans. That's the only difference that I've noticed, but it is more of a design issue than anything. – LucasP Jan 08 '16 at 14:32
@DavidR You are right. They can be used interchangeable to inject Spring beans. – Krzysztof Majewski Jan 08 '16 at 14:34
3

Autowired is just the legacy version of Inject. They are synonymous with the exception that Autowired forces a dependency on Spring. – DavidR Jan 08 '16 at 14:34
1

And it supports the "required" parameter which Inject doesn't support. So if you need this parameter, you have to use Autowired. – dunni Jan 08 '16 at 14:54

Difference between @inject annotation and Constructor/Setter + XML config Injection?

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