title: Hibernate: How to fix "identifier of an instance altered from X to Y"?
body: <pre><code>org.hibernate.HibernateException: identifier of an instance 
  of org.cometd.hibernate.User altered from 12 to 3
  </code></pre>
  
  <p>in fact, my <code>user</code> table is really must dynamically change its value, my Java app is multithreaded.
  Any ideas how to fix it? </p>