What common mistaken approaches to dependency injection in Spring do you know?

Common mistakes when implementing dependencies in Spring:

• Using new to create dependencies instead of injecting through Spring — leads to losing DI benefits and testing difficulties.

• Lack of annotations or incorrect usage (@Autowired, @Component, @Service), which prevents Spring from finding or injecting the required bean.

• Injecting dependencies through fields without using constructors or setters — complicates testing and violates encapsulation.

• Cyclic dependencies, where two beans depend on each other directly, causing errors during context creation.

• Using @Autowired without specifying optionality (required=false), which can lead to errors if the bean is not found.

• Injecting too many dependencies into a single class, indicating a violation of the single responsibility principle.

The correct approach is to use constructor injection, annotate classes and dependencies, avoid manual object creation, and monitor the application's architecture.