title: JPA/Hibernate instance of not working
body: <p>Imagine a situation:</p>
  
  <pre><code>@javax.persistence.Inheritance(strategy=javax.persistence.InheritanceType.JOINED)
  @javax.persistence.DiscriminatorColumn
  @javax.persistence.Entity
  @javax.persistence.Table(name="PARENT")
  public abstract class Parent{
  ...
  }
  
  @javax.persistence.Entity
  @javax.persistence.Table(name="A")
  public class A extends Parent{
  ...
  }
  
  @javax.persistence.Entity
  @javax.persistence.Table(name="B")
  public class B extends Parent{
  ...
  }
  
  
  Parent p = new A();
  </code></pre>
  
  <p>Now we call this:</p>
  
  <pre><code>p instance of A
  </code></pre>
  
  <p>always returns <strong>false</strong>!!</p>
  
  <p>works ok on OpenJPA!</p>
  
  <p>Should I file a bug? Hibernate 4.3.10</p>