JHipster: jhi-alert-error element and server side form validation?
<p>I am using JHipster 3.3. In the generated "entity"-dialog.html, I noticed the tag <strong>jhi-alert-error</strong> element will display server validation error so for example if a field is mandatory as specified in entity JPA class like</p>

<pre><code>    @NotNull
    private String name;
</code></pre>

<p>Then error message for that field will be returned after clicking the Submit button if value of the field is empty.</p>

<p>So questions:</p>

<ol>
<li><p>How is <strong>jhi-alert-error</strong> implemented? I can't seem to see its implementation</p></li>
<li><p>I tried tweaking JPA annotation to make a field unique BUT this time no error message will be displayed in <strong>jhi-alert-error</strong> if I break the unique constraint by adding 2 records having the same value for the field, 
E.g.</p>

<p>// note 'unique=true' below</p>

<blockquote>
  <p>@NotNull
     @Column(name = "name", unique=true)<br>
  private String name;</p>
</blockquote>

<p>or</p></li>
</ol>

<blockquote>
  <p>@Table(name="Module", uniqueConstraints = @UniqueConstraint(columnNames = "Name"))
     public Class Module implements Serializable { ...</p>
</blockquote>

<p>So how would I go about implementing my own server side form validation so error messages will be displayed in <strong>jhi-alert-error</strong> when the unique constraint of a field is broken after clicking the Submit button?</p>

<p>Thanks in advance,</p>