Which type of Dependency Injection it is when we have @Autowire on a class field?

Question

One way is the DI using setter methods. Other way is using constructor.

I am just curious to know which type of DI the following way is :

public class Test {

    @Autowired
    TestService service;
    ...
}

Answer 1

That is "field injection". Generally you can choose from 3 types:

• Field injection
• Constructor injection
• Setter injection

Each of them has advantages and disadvantages. During the testing field injection is normal practice.

Answer 2

In case of @Autowiring in a class like:

public class Test {

    @Autowired
    TestService service;
    ...
}

Autowire your object on using reflection, hence no need for Setter methods

Check this post: How does Spring @Autowired work