title: Difference between using @OneToMany and @ManyToMany
body: <p>I am having some trouble understanding the difference between <code>@OneToMany</code> and <code>@ManyToMany</code>. When I use <code>@OneToMany</code> it defaults to create a JoinTable and if you add the mappedBy attribute you will have bidirectional relationship between two entities.  </p>
  
  <p>I have a <code>Question</code> that may belong to many <code>Categories</code>, and one <code>Category</code> may belong to many <code>Questions</code>. I don't understand if I should use <code>@ManyToMany</code> or <code>@OneToMany</code> because for me it seems exactly the same thing, but it is probably not. </p>
  
  <p>Could somebody explain it?</p>