What knowledge do you have about using proxies in Spring Framework?

In the Spring Framework, proxies are used to implement aspect-oriented programming (AOP), manage transactions, lazy initialization, and other functions that require wrapping objects.

Main points of using proxies in Spring:

• JDK Dynamic Proxy: creates a proxy based on interfaces. If a class implements an interface, Spring will by default create a proxy implementing that interface.
• CGLIB Proxy: creates a proxy by inheriting from the target class. Used if the class does not implement an interface or explicitly specified.

Proxies intercept method calls and can perform additional logic before or after the original method call (e.g., logging, permission checks, transaction management).

Example of using a proxy for transaction management:

@Service
public class UserService {
    @Transactional
    public void createUser(User user) {
        // business logic
    }
}

Spring will create a proxy for UserService, which will automatically open and close a transaction when calling createUser.

You can also create your own proxies using ProxyFactory or use AOP configuration to define pointcuts and advice.