title: @RequestBody how to differentiate an unsent value from a null value?
body: <pre><code>@PatchMapping("/update")
  HttpEntity&lt;String&gt; updateOnlyIfFieldIsPresent(@RequestBody Person person) {
      if(person.name!=null) //here
  }
  </code></pre>
  
  <p>how to differentiate an unsent value from a null value? How can I detect if client sent null or skipped field?</p>