title: Hibernate merge creates copy of passed entity
body: <p>There is much information available on <code>merge</code> however I am confused as to why <code>merge</code> creates a copy of passed entity instead of persisting the passed entity itself?</p>
  
  <p>Why is there a need of <code>merge</code> method? What is the use of calling <code>merge</code> method on new object?</p>