getting ConstraintViolationException instead of MethodArgumentNotValidException when using @valid with @RequestBody in the controller

i am continuing my journey to learn Spring boot, right now i am stuck between two similar kind of exceptions, wherever i found i have got the answer that if @valid or @validate used at controller/service level along with @RequestBody we should get MethodArgumentNotValidException whereas, i am getting ConstraintViolationException during post and update API calls. again and again the call is going in globalExceptionHandler method of ExceptionHAndler class, where it is showing constraintviolationexception.

PostController.java

@RestController
@RequestMapping("/api/posts")
public class PostController {
    
    @Autowired
    private PostService postService;

    //rest API endpoint to post http:localhost:8080/api/posts
    @PostMapping
    public ResponseEntity<PostDTO> createPost(@Valid @RequestBody PostDTO postDTO){
        return new ResponseEntity<>(postService.createPost(postDTO),HttpStatus.CREATED);
    }
    
    @PostMapping(path = "/multiple")
    public ResponseEntity<List<PostDTO>> createMultiplePosts(@Valid @RequestBody List<PostDTO> postDTO){
        
        return new ResponseEntity<>(postService.createMultiplePosts(postDTO),HttpStatus.CREATED);
    }

Entity Class:

Posts.java

@Entity
@Table(name = "posts", uniqueConstraints = {@UniqueConstraint(columnNames = {"titles"})})
public class Posts {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;
    @Column(name = "titles")
    @NotEmpty
    @Size(min = 2,message = "post title should contain atleast 2 character")
    private String title;
    @Column(name = "description")
    @NotEmpty
    @Size(min = 10,message = "post description should contain atleast 2 character")
    private String description;
    @Column(name = "content")
    @NotEmpty
    private String content;

GlobalException.java

@ControllerAdvice
public class GlobalException extends ResponseEntityExceptionHandler {
    
    private static final Logger logger = LoggerFactory.getLogger(GlobalException.class);
    
    @ExceptionHandler(ResouceNotFoundException.class)
    ResponseEntity<ErrorDetails> PostNotFoundExceptionHandler(ResouceNotFoundException exception, WebRequest webRequest){
        
        ErrorDetails errorDetails =new ErrorDetails(new Date(),exception.getMessage(),webRequest.getDescription(false));
        return new ResponseEntity<>(errorDetails,HttpStatus.NOT_FOUND);
    }
    
    @ExceptionHandler(BlogApiException.class)
    ResponseEntity<ErrorDetails> CommentNotFoundExceptionHandler(BlogApiException exception, WebRequest webRequest){
        
        ErrorDetails errorDetails =new ErrorDetails(new Date(),exception.getMessage(),webRequest.getDescription(false));
        return new ResponseEntity<>(errorDetails,HttpStatus.NOT_FOUND);
    }
    
    
    @Override
//  @ExceptionHandler(MethodArgumentNotValidException.class)
    protected ResponseEntity<Object> handleMethodArgumentNotValid(
            MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatusCode status, WebRequest request){
        
        logger.info("inside handleMethodArgumentNotValid class");
        Map<String, String> errorsMap =new HashMap<>();
        ex.getBindingResult().getAllErrors().forEach((error)->{
        
            String fieldNameString = ((FieldError)error).getField();
            String messageString = error.getDefaultMessage();
            errorsMap.put(fieldNameString, messageString);
        });
        return new ResponseEntity<>(errorsMap,HttpStatus.BAD_REQUEST);
    }
    
    @ExceptionHandler(Exception.class)
    ResponseEntity<ErrorDetails> GlobalExceptionHandler(Exception exception, WebRequest webRequest){
        logger.info("inside GlobalExceptionHandler class");
        ErrorDetails errorDetails =new ErrorDetails(new Date(),exception.getMessage(),webRequest.getDescription(false));
        return new ResponseEntity<>(errorDetails,HttpStatus.BAD_REQUEST);
    }

}

i tried modifying RequestBody JSON, tried @validated annotation at class level, and at method level after @RequestBody annotation as well, still getting same exception. please help me to understand why am I getting this exception, tried playing with versions of spring boot starter validation dependency. currently using 3.0.4 version of starter-validation dependency Java version is 17.0.7

Why do you think you should get MethodArgumentNotValidException? ConstraintViolationException seems to be totally reasonable exception to expect, when some constraints were violated by your request body. I don't see a problem here. Just change your ExceptionHandler to catch ConstraintViolationException and do whatever you want with it.