Spring Boot bean validator not triggering

I am using the latest stable version of springboot and spring-validator, however the bean validation is not being called at all. Bellow my gradle.kts, Bean and Controller:

plugins {
    java
    id("org.springframework.boot") version "3.2.2"
    id("io.spring.dependency-management") version "1.1.4"
    id("org.jetbrains.kotlin.plugin.spring") version "1.9.22"
    kotlin("plugin.noarg") version "1.9.22"
    kotlin("plugin.jpa") version "1.9.22"
    kotlin("jvm")
}

group = "com.study.alura.challenge"
version = "0.0.1-SNAPSHOT"

java {
}

repositories {
    mavenCentral()
}

dependencies {
    // Spring
    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("org.springframework.boot:spring-boot-starter-log4j2")
    developmentOnly("org.springframework.boot:spring-boot-devtools")
    implementation("org.springframework.boot:spring-boot-starter-validation:3.2.2")

    //Database
    implementation("org.flywaydb:flyway-core")
    runtimeOnly("org.postgresql:postgresql")

    //AWS
    implementation("com.amazonaws:aws-java-sdk:1.12.644")

    //Kotlin
    runtimeOnly("org.jetbrains.kotlin:kotlin-reflect:1.9.22")
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.16.1")
    implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.16.1")

    //Testing
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    implementation(kotlin("stdlib-jdk8"))
}

dependencyManagement {
    imports {
        mavenBom("org.springframework.cloud:spring-cloud-dependencies:2023.0.0")
    }
}

configurations {
    all {
        exclude("org.springframework.boot", module = "spring-boot-starter-logging")
    }
}

tasks.withType<Test> {
    useJUnitPlatform()
}
kotlin {
    jvmToolchain(21)
}

package com.study.alura.challenge.journeymiles.user.controller

import com.study.alura.challenge.journeymiles.user.dto.request.CreateUserRequestDTO
import com.study.alura.challenge.journeymiles.user.dto.response.CreateUserResponseDTO
import com.study.alura.challenge.journeymiles.user.service.UserService
import jakarta.validation.Valid
import org.apache.logging.log4j.LogManager
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.bind.annotation.RequestBody
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController

@RestController
@RequestMapping("/users")
class UserController(private val userService: UserService) {

    private val logger = LogManager.getLogger(this::class.java)

    @PostMapping
    fun create(@RequestBody @Valid createUserRequestDTO: CreateUserRequestDTO): ResponseEntity<CreateUserResponseDTO> {
        return ResponseEntity.ok(
            userService.createUser(createUserRequestDTO).also {
                logger.info("Created a new user with id: ${it.id}")
            }
        )
    }
}

package com.study.alura.challenge.journeymiles.user.dto.request

import jakarta.validation.constraints.Email
import jakarta.validation.constraints.NotNull
import jakarta.validation.constraints.Size
import java.io.Serializable

data class CreateUserRequestDTO(
    @NotNull(message = "The name field is mandatory")
    @Size(min = 3, max = 100, message = "The name field must bet between 3 and 100 chars")
    val name: String,
    @NotNull(message = "The email field is mandatory")
    @Email
    val email: String,
    @NotNull(message = "The password field is mandatory")
    @Size(min = 6, max = 12, message = "The password field must bet between 6 and 12 chars")
    val password: String
): Serializable

Does anyone has any hints on what's missing?

I have followed almost every tutorial on the internet and still cant find what is wrong with the code

Using bean validation, and triggering validation

UPDATE Sachin's answer worked!

You maybe mixing Java validation with Kotlin's. Try

data class CreateUserRequestDTO(
    @field:NotNull(message = "The name field is mandatory")
    @field:Size(min = 3, max = 100, message = "The name field must bet between 3 and 100 chars")
    val name: String,
    @field:NotNull(message = "The email field is mandatory")
    @field:Email
    val email: String,
    @field:NotNull(message = "The password field is mandatory")
    @field:Size(min = 6, max = 12, message = "The password field must bet between 6 and 12 chars")
    val password: String
): Serializable

You could also check out https://www.baeldung.com/kotlin/valid-spring-annotation