Solution: CourseHandler: | public List<Course> getCoursesForInstructor(CmtUser instructor){ | try{ | Query q = em.createQuery( | "SELECT c FROM Course c" + | " WHERE c.instructor = :instructor"); | q.setParameter("instructor",instructor); | | List<Course> courses = (List<Course>) q.getResultList(); | return courses ; | | } | | catch(EntityNotFoundException ex){ | System.out.println("FEHLER!!!!"+ex); | } | return null; | } Course: @Entity | public class Course implements Serializable{ | @Id | @GeneratedValue(strategy = GenerationType.AUTO) | private Long id; | | private String title; | private String abbreviation; | private String description; | private String semester; | @Column(columnDefinition="BOOL") | private boolean active = false; | | //unidirektional | @ManyToOne | @JoinColumn(name="instructor") | private CmtUser instructor; | ... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4198448#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...