title: Server Side validation doesnt seems to work in SpringBoot 2.3.1.RELEASE
body: <p>I have a POJO class and its API method. I want to validate user field input but it doesnt seems to work. I have used @Size() annotation in my POJO class but it is not working. Below is snippet of my logic structure.</p>
  
  <p><strong>POJO Class</strong></p>
  
  <pre><code>@Entity
  public class Address {
  
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      private long addressId;
  
      @NotNull
      @Size(min=10, max=100, message="Please enter between {min}-{max} characters")
      private String addressLine;
  </code></pre>
  
  <p><strong>API Class method</strong></p>
  
  <pre><code>@PostMapping(value="/add", produces = MediaType.APPLICATION_JSON_VALUE, consumes=MediaType.APPLICATION_JSON_VALUE)
      public @ResponseBody String addAddress( @RequestBody @Valid Address address, BindingResult result)
      {
          if(result.hasErrors()) {
              return ErrorUtils.customErrors(result.getAllErrors());
          } else {
              return addressService.addAddress(address);
          }
      }
  </code></pre>
  
  <p>and i am creating JSON request for <strong>addAddress (/add) method</strong> and prompting the error in UI form. My JSON response handler is in jquery validator like below..</p>
  
  <pre><code>function saveRequestedData(frm, data, type) {
      $.ajax({
          contentType:"application/json; charset=utf-8",
          type:frm.attr("method"),
          url:frm.attr("action"),
          dataType:'json',
          data:JSON.stringify(data),
          success:function(data) {
              if(data.status == "success") {
              alert(data.message);
              toastr.success(data.message, data.title, {
                  closeButton:true
              });
              fetchList(type);
              }
              else {
                  toastr.error(data.message, data.title, {
                      allowHtml:true,
                      closeButton:true
                  });
              }
          }
      });
  }   
  
  </code></pre>
  
  <p>It seems only @NotNull seems to work not @Size and @Valid annotation. 
  <strong>As per Spring Boot Release notes</strong>, Starting from version 2.3.0.RELEASE Spring Boot Web and WebFlux starters no longer depend on the validation starter, so i have added spring-boot-starter-validation in my pom.xml manually. 
  But nothing seems to work.</p>