title: HornetQ Core API and JMS
body: <p>I have few questions regarding HornetQ:</p>
  
  <ol>
  <li><p>What are differences between HornetQ core API and the JMS API ?</p></li>
  <li><p>is there any advantage or disadvantage on using one of these ?</p></li>
  <li><p>Is it true to say if I use the core API and then I decide to
      change my Messaging Bus (let's say to ActiveMQ) then I have to
      change all my codes ?</p></li>
  </ol>