Reference documentation sample for MethodValidationPostProcessor is missing a static keyword

[ozooxo]

I followed the Spring official document to define MethodValidationPostProcessor for bean validation. But I am triggering the below warning:

2024-05-30T17:53:41.988-04:00 WARN 74724 --- [demo] [ main] trationDelegate$BeanPostProcessorChecker : Bean 'appConfig' of type [com.example.demo.AppConfig$$SpringCGLIB$$0] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying). The currently created BeanPostProcessor [validationPostProcessor] is declared through a non-static factory method on that class; consider declaring it as static instead.

To reproduce it, see https://github.com/ozooxo/spring-jakarta-validation-post-processors-warning

• Commit #1 is solely generated by spring starter.
• Commit #2 defines the MethodValidationPostProcessor bean following the doc.

then if I ./gradlew bootRun I'll see the above warning.

It seems that a similar problem has been coming up before in ~2017:

• When I use spring-boot to create an object that supports transactions, the object can not be correctly created  spring-boot#9416
• AbstractMethodError when calling validated method of MethodValidationPostProcessor is using a @Lazy validator [SPR-15629] #20188
• Follow-up: AbstractMethodError when calling validated method of MethodValidationPostProcessor is using a @Lazy validator [SPR-15807] #20362

but it has been coming back.

[quaff]

Have you tried adding @JvmStatic on fun validationPostProcessor()?

[sbrannen]

Have you tried adding @JvmStatic on fun validationPostProcessor()?

@ozooxo, please try what @quaff suggested and let us know if that gets rid of the warning for you.

[snicoll]

The warning is as follows:

Bean 'appConfig' of type [com.example.demo.AppConfig$$SpringCGLIB$$0] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying). The currently created BeanPostProcessor [validationPostProcessor] is declared through a non-static factory method on that class; consider declaring it as static instead.

The documentation is wrong, that Java example should have the static keyword. We'll get that fixed but, as others have said, please read the warning in the log. I don't know how to achieve that with Kotlin though.

As for the sample demo, if you're using Spring Boot, you don't need to register that bean as the auto-configuration does that already.

[sbrannen]

I don't know how to achieve that with Kotlin though.

I think it would look like this:

@Configuration
class AppConfig {

    companion object {
        @JvmStatic
        @Bean
        fun validationPostProcessor(): MethodValidationPostProcessor {
            return MethodValidationPostProcessor()
        }
    }
}

[snicoll]

Yes, I am aware how @JvmStatic works. Have you tried it?

@sdeleuze offered to look why the code above doesn't work.

[ozooxo]

As for the sample demo, if you're using Spring Boot, you don't need to register that bean as the auto-configuration does that already.

I am using Spring boot, and remove this bean can get rid of the warning. However,

• For unit tests to cover @Validated and @Valid, only @SpringBootTest instead of @ExtendWith(SpringExtension::class) can work. That makes sense because the auto-configured bean is not in my @Import list.
• Guess then I can no longer customize the post processor e.g. processor.setAdaptConstraintViolations(true).

To see this, I have commit #3 and in it the testInsertWithInvalidEmail() test can raise ConstraintViolationException as expected. And with commit #4 in order for the tests to still pass, I need @SpringBootTest.

[sdeleuze]

Documentation fixed for the Java use case. Declaring BeanPostProcessor beans is (surprisingly) not possible yet with Kotlin but this will be supported as of 6.2 via #32946. With previous versions, please use Java classes as a workaround.