delete the autowire from controller and replace it with normal initialization

Question

My current codes contain @autowired but I would like to remove it and then initialize it with code. Please vote down my questions if you found it hard to understand but PLEASE at least comment so that I can re-edit as I am new to this annotation stuff and still getting my hands wet with it.

Below shows my code and from what I could understand about autowired is that it takes the values from class "Test" and wire the values to testing. What about if I remove this @autowired from the code? How can I still make it executable? I mean, if I remove the @autowired, how can I still initialized the values in this same line instead of using the wiring annotation? - Reason I wanted to try this is to see my understanding and at the same time see more different examples to improve my understranding

 @Autowired
  @Qualifier("testing")
  Test testing;

I dont have expected results because I just want to understand the annotations and see whether my understanding is correct.

Answer 1

There are three ways to inject an autowired dependency (using spring) into a bean:

1. Autowiring the field itself

   @Autowired
   private Test test;
   
   @Autowired
   private SomethingService somethingService;
   

2. Autowiring a setter

   private Test test;
   private SomethingService somethingService;
   
   @Autowired
   public void setTest(Test test) {
       this.test = test;
   }
   
   @Autowired
   public void setSomethingService(SomethingService somethingService) {
       this.somethingService = somethingService;
   }
   

3. Autowiring the constructor (which doesn't need an annotation):

   public class Something {
   
       private Test test;
       private SomethingService somethingService;
   
       public Something(Test test, SomethingService somethingService) {
           this.test = test;
           this.somethingService = somethingService;
       }
   
       ...
   }
   

A benefit of using the third approach is that when you construct an instance of the class for testing, you can pass in any implementations you want for the dependencies.