title: Using @ElementCollection and @CollectionTable on @MappedSuperclass base class with EclipseLink
body: <p>I have a base class defined as follow:  </p>
  
  <pre><code>@MappedSuperclass
  public abstract class BaseUser {
      @ElementCollection(fetch = FetchType.EAGER)
      @CollectionTable(name = "user_tags",
          joinColumns = {
                  @JoinColumn(name = "owner_id", referencedColumnName= "tagName")})
      public Set&lt;String&gt; getTags() {...}
  </code></pre>
  
  <p>And a bunch of derived user classes which extends BaseUser.<br>
  With Hibernate a single "user_tags" table was created for all the derived classes (which was what I wanted).<br>
  After moving to EclipseLink it seems the engine tried to add the "owner_id" and the "tagName" columns over and over as the number of the derived classes which obviously result with table creation failure. 
  Is there a way to get the same behavior as Hibernate in EclipseLink?
  What does the JPA spec expects in such a scenario? </p>