title: Grails rejected value [null]
body: <p>I'm getting a validation error during save on <code>field 'adjustmentType': rejected value [null]</code> I'm a little puzzled by this error because I have my mapping set to allow nullables</p>
  
  <pre><code>static mapping = {  
      columns{
          adjustmentType column: 'adjustment_type', length: 10, sqlType:"char", nullable: true
      }
  }
  </code></pre>
  
  <p>The other part I don't understand is why I'm getting an exception rather than a validation message. </p>
  
  <p>I have the following code</p>
  
  <pre><code>&lt;g:hasErrors bean="${recoveryDetailInstance}"&gt;
      &lt;ul class="errors" role="alert"&gt;
          &lt;g:eachError bean="${recoveryDetailInstance}" var="error"&gt;
              &lt;li
                  &lt;g:if test="${error in org.springframework.validation.FieldError}"&gt;data-field-id="${error.field}"&lt;/g:if&gt;&gt;&lt;g:message
                      error="${error}" /&gt;&lt;/li&gt;
          &lt;/g:eachError&gt;
      &lt;/ul&gt;
  &lt;/g:hasErrors&gt;
  </code></pre>
  
  <p>Controller</p>
  
  <pre><code>@Transactional
  def update() {  
      def recoveryDetailInstance = RecoveryDetail.get(new RecoveryDetail(params));
  
  
      if (recoveryDetailInstance == null) {
          redirect (uri:'/')
          return
      }
  
      recoveryDetailInstance.save(flush:true,failOnError:true)
  
      redirect (controller:"recoveryDetail", action:"edit", params:recoveryDetailInstance.getPK())
  }
  </code></pre>