title: JPA differences between Join and JoinSet
body: <p>As the title say, I want to know the differences among these two methods.</p>
  
  <p>Specifically I want to know the difference between:</p>
  
  <p><a href="http://docs.oracle.com/javaee/6/api/javax/persistence/criteria/From.html#join%28java.lang.String%29" rel="noreferrer">join(String arg)</a>
  AND 
  <a href="http://docs.oracle.com/javaee/6/api/javax/persistence/criteria/From.html#joinSet%28java.lang.String%29" rel="noreferrer">joinSet(String arg)</a></p>
  
  <p>As I can use <em>join(String arg)</em> even if the attribute is a Set, but not the opposite, namely using <em>joinSet(String arg)</em> on an attribute that is not a Set.</p>
  
  <p>Thanks.</p>