Hi, anybody know why using @Validated on a Controller class in Spring could mess up with constructor injections? I simply get null values for all injected objects. The problem came out after migration to Kotlin from Java.

Code?

It works: @RestController @Validated public class TestController { private NativeWebRequest request; @Autowired public TestController(NativeWebRequest request) { this.request = request; } @GetMapping( value = "/test/{countryCode}", produces = {"application/json"}) public ResponseEntity<String> getTestResponse(@Pattern(regexp = "^[A-Z]{2}$") String countryCode) { return new ResponseEntity<>("ok", HttpStatus.OK); } } It does not work: @RestController @Validated open class TestController2 @Autowired constructor(private val request: NativeWebRequest) { @GetMapping(value = ["/test2/{countryCode}"], produces = ["application/json"]) fun getTest2Response(countryCode: @Pattern(regexp = "^[A-Z]{2}$") String?): ResponseEntity<String> { return ResponseEntity("ok", HttpStatus.OK) } } It works: @RestController //@Validated open class TestController2 @Autowired constructor(private val request: NativeWebRequest) { @GetMapping(value = ["/test2/{countryCode}"], produces = ["application/json"]) fun getTest2Response(countryCode: @Pattern(regexp = "^[A-Z]{2}$") String?): ResponseEntity<String> { return ResponseEntity("ok", HttpStatus.OK) } }

well, everything works fine for me note that

ConstraintViolationException

is not handled in the first request

THanks, any idea why it could not work on my side? @RestController @Validated open class TestController2 @Autowired constructor(private val thing: Thing) { @GetMapping(value = ["/test2/{countryCode}"]) fun getTest2Response(countryCode: @Pattern(regexp = "^[A-Z]{2}$") String?): ResponseEntity<String> { return ResponseEntity(thing.value, HttpStatus.OK) } }

I see you use

open

do you use spring support plugin for kotlin?

Yes but for groovy version gradle: id 'org.jetbrains.kotlin.jvm' version '1.6.21'

removed the spring plugin from my build config:

plugins { id 'org.springframework.boot' version '2.6.7' id 'io.spring.dependency-management' version '1.0.11.RELEASE' id 'java' id 'org.jetbrains.kotlin.jvm' version '1.6.21' }

well, repalce it with:

plugins {
    id 'org.springframework.boot' version '2.6.7'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'org.jetbrains.kotlin.jvm' version '1.6.21'
    id "org.jetbrains.kotlin.plugin.spring" version '1.6.21'
}

Wow, it works! I missed that 🙂 Thank you very much!

Hi @Andrzej Sawoniewicz, cool you issue is fixed! I believe you could define your controller like this also:

@Validated

@RestController

class TestController(private val request: NativeWebRequest)

If you have your spring plug there is no need of "open", no need for "@Autowired" and no need for the explicit "constructor" I know it is not super important but you can remove some boilerplate