Dto validations in springboot applications are not working

I am trying to implement validations in my application for register user API. i have created RegisterRequest.java dto and my controller is having below code, neither bindingresult working nor the validations.

@PostMapping("/register")public ResponseEntity<AuthenticationResponse> register(        @RequestBody @Valid RegisterRequest request,     BindingResult bindingResult) {    request.setRole(Role.USER);    if(bindingResult.hasErrors()){        throw new DataValidationException();    }    return ResponseEntity.ok(authenticationService.register(request));}

RegisterRequest.java

import javax.validation.constraints.Email;import javax.validation.constraints.NotBlank;import javax.validation.constraints.Size;import com.jobposting.entity.Role;import lombok.AllArgsConstructor;import lombok.Builder;import lombok.Data;import lombok.NoArgsConstructor;@Data@Builder@AllArgsConstructor@NoArgsConstructorpublic class RegisterRequest {    @NotBlank(message = "First name is required")    private String firstname;    private String lastname;    @NotBlank(message = "Email is required")    @Email(message = "Email should be valid")    private String email;    @NotBlank(message = "Password is required")    @Size(min = 8, message = "Password must be at least 8 characters long")    private String password;    @Size(min = 10, max = 10, message = "Contact number must be 10 digits long")    @NotBlank(message = "Contact is required")    private String contact;    private boolean whatsappConsent;    private Role role;}

i am calling the api with below body

{"firstname":"john","lastname":"doe","email":"","password":"1234","contact":"81808880","whatsappConsent":true}

and getting response which I have handled in service layer, I am expecting my code to not proceed till the service layer.

{"dateTime": "2024-05-25T18:24:01.0826414","message": "User already present in database","details": "uri=/api/v1/auth/register"}