SPRING - DEPENDENCY INJECTION VS. INVERSION OF CONTROL

Consider you have an application which has a text editor component and you want to provide spell checking. Your standard code would look something like this:

public class TextEditor {
   private SpellChecker spellChecker;
   
   public TextEditor() {
      spellChecker = new SpellChecker();
   }
}

What we've done here is create a dependency between the TextEditor and the SpellChecker. In an inversion of control scenario we would instead do something like this:

public class TextEditor {
   private SpellChecker spellChecker;
   
   public TextEditor(SpellChecker spellChecker) {
      this.spellChecker = spellChecker;
   }
}

Here TextEditor should not worry about SpellChecker implementation. The SpellChecker will be implemented independently and will be provided to TextEditor at the time of TextEditor instantiation and this entire procedure is controlled by the Spring Framework.