title: Hibernate validator validate field with @Length annotation and without @NotEmpty annotation
body: <p>I have found <a href="https://stackoverflow.com/questions/14155911/hibernate-validator-validate-empty-field-where-is-not-notempty">copy of my question on stackoverflow</a>, but there are no answer, except regular expression.</p>
  
  <p>So i have a model with field "phoneNumber", which has a validation annotation @Length:</p>
  
  <pre><code>@Length(min = 3, max = 7)
  private String phoneNumber;
  </code></pre>
  
  <p>It has not annotation @NotEmpty, so i wont check filling of it. But hibernate gives me an error, that length must be from 3 to 7. But this field may be empty... What's wrong with me? Or with him?</p>