Clarification required on Spring Boot validator

Question

Folks, I have a project in SpringBoot 3.2.2 and am trying to add validators (@NotEmpty) to the input - but, it doesn't seem to work. Here are the things that I have already done / tried.

1. Added the following dependency

   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-validation</artifactId>
       <version>3.1.0</version>
   </dependency>
   

Note: I also tried with hibernate-validator dependency as well - but, no luck there as well

2. I added @Validated annotation to my controller + @Valid annotation to the parameter - highlighted below in the code

   @RestController
   @Validated
   @RequestMapping("/api/posts")
   public class PostController {
       private PostService postService;
   
       public PostController(PostService postService) {
           this.postService = postService;
       }
   
       @PostMapping
       public ResponseEntity<PostDto> createPost (@Valid @RequestBody PostDto postDto) {       
           return new ResponseEntity<>(postService.createPost(postDto), HttpStatus.CREATED);
       }
   

3. In my DTO class, I added the @NotEmpty annotation - importing the jakarta.validation.constraints. I read that the javax.validation.constraints doesn't work for SpringBoot projects greater than 3.x version.

   import jakarta.validation.constraints.NotEmpty;
   public class PostDto {
       private Long id;
   
       @NotEmpty (message = "Title cannot be empty")
       private String title;
   

I also tried with hibernate-validator dependency as well - but, no luck there as well.

Thanks in advance!