Can you name and explain the types of Proxy used in Spring Framework?

Spring Framework uses two main types of proxies for aspect-oriented programming (AOP) and other mechanisms:

1. JDK Dynamic Proxy

   • Creates proxies based on interfaces.
   • Works only with objects that implement at least one interface.
   • The proxy implements the same interfaces as the target object.

2. CGLIB Proxy

   • Creates proxies by inheriting from the target class.
   • Used if the object does not have interfaces or if explicitly configured to use class-based proxies.
   • Allows proxying classes without interfaces.

Spring automatically chooses the proxy type: if interfaces are present — JDK Proxy, otherwise CGLIB.

Example configuration:

@Service
public class MyService {
    public void doWork() {
        // ...
    }
}

When using AOP, Spring will create a proxy for MyService, selecting the appropriate type based on the presence of interfaces.