Spring AOP cannot generate CGLIB proxy for record class

[ColorDreams]

Hi

I used record classes on Controller and Service to simplify the loading of Bean, but it doesn't seem to work, suggesting that CGLIB subclasses cannot be generated.

Controller: I can understand that, after all, it doesn't implement any interface, but Service has implemented the interface, and it still can't be enhanced by JDK Proxy.

The following is the pseudo code I used.

@Validated
@RestController
@RequestMapping("/users")
public record UserController(IUserService userService) {
    // some biz code...
}

@Service
public record UserServiceImpl(UserMapper userMapper) implements IUserService {
    // some biz code...
}

Interestingly, this code did not report errors at compile time, and IDEA can also identify their dependencies normally.

It would be great if the record class could be used on stateless bean, although Java is not Kotlin.

[sbrannen]

A Java record can in fact not be proxied using CGLIB, since a record class is final which prevents CGLIB from implementing a dynamic subclass.

So, in general, that is to be expected.

As you pointed out, UserController does not implement any interfaces. Thus, if it is implemented as a record Spring AOP cannot generate a dynamic proxy (interface-based) or CGLIB subclass proxy. In other words, using a record for your UserController is simply not an option.

Regarding UserServiceImpl, you are correct. Spring AOP is capable of generating a dynamic proxy for it based on the IUserService interface that it implements. However, if you are using Spring Boot, please note that Spring Boot defaults to generating CGLIB proxies via its spring.aop.proxy-target-class configuration property. You could try switching that to false in your application.

In Spring Framework 7.0, we are introducing support to configure the type of proxy you need to use on a per-bean basis. In fact, @jhoeller literally implemented this yesterday. This will be configurable via the new @Proxyable annotation.

• See Introduce @Proxyable annotation for bean-specific proxy type #35296

In light of the above, I am closing this issue.