Annotation @Valid in RestController always returning status code 200

I followed multiple posts online like https://www.javatpoint.com/restful-web-services-validations https://reflectoring.io/bean-validation-with-spring-boot/ and many more.

Everywhere it is written that just by adding @Valid in-front of @RequestBody will check validation of the input. But for me it always returns status code as 200 although using JUnit test cases I am able to validate all the restrictions.

Also I followed posts like Spring Boot Validations with annotations And added BindingResult as 2nd parameter, still the behaviour is same and bindingResult object shows 0 errors.

Details are below:

DTO Class:

package practice.corejava.validators.dto;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.NotNull;
import jakarta.validation.constraints.Positive;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class UserData {

    @NotBlank(message = "Name should not be blank")
    private String name;

    @NotNull(message = "Age should not be null")
    @Positive(message = "Age should be positive")
    private Integer age;

}

Controller Class: (Always returning 201 via Postman)

package practice.corejava.validators.controller;

import practice.corejava.validators.dto.UserData;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.BindingResult;
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;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import jakarta.validation.Valid;

import java.net.URI;

@RestController
@RequestMapping("api/v1/validations")
public class ValidationsController {

    @PostMapping(value = "/user-data", consumes = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<UserData> createUserData(@Valid @RequestBody UserData userData) {
        URI location = ServletUriComponentsBuilder.fromCurrentRequest().path("/{name}").buildAndExpand(userData.getName()).toUri();
        return ResponseEntity.created(location).build();
    }

}

JUnit Test Class: (Test cases are succeeding)

package practice.corejava.validators.dto;

import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

import jakarta.validation.ConstraintViolation;
import jakarta.validation.Validation;
import jakarta.validation.Validator;
import jakarta.validation.ValidatorFactory;
import java.util.Set;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class UserDataTest {

    private static Validator validator;

    @BeforeAll
    public static void setUp() {
        try (ValidatorFactory factory = Validation.buildDefaultValidatorFactory()) {
            validator = factory.getValidator();
        }
    }

    @Test
    void all_validation_success() {
        UserData userData = new UserData("SomeName", 30);
        Set<ConstraintViolation<UserData>> constraintViolations = validator.validate(userData);
        assertEquals(0, constraintViolations.size());
    }

    @Test
    void name_blank() {
        UserData userData = new UserData("", 30);
        Set<ConstraintViolation<UserData>> constraintViolations = validator.validate(userData);
        assertEquals(1, constraintViolations.size());
        assertEquals("Name should not be blank", constraintViolations.iterator().next().getMessage());
    }

}

Postman request body: Expected 400 but 201 coming as status code

{
    "name" : null,
    "age" : 30
}

See "Dependencies and Versions" details below:

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.1.3</version>
    <relativePath/>
</parent>

<properties>
    <java.version>17</java.version>
</properties>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>jakarta.validation</groupId>
    <artifactId>jakarta.validation-api</artifactId>
    <version>3.0.2</version>
</dependency>

As suggested by M. Deinum in comments, the dependencies that I was using was incompatible with Spring boot 3.x. and hence the response was not coming as expected. After updating with the suggested changes, now it is perfectly working. Thanks a lot for your suggestions and time @M. Deinum