Hi. Im developing a system that stores courses that participants can apply to. I'm presenting the enrollments in a JTree in the courseadministratorGUI.

My problem is that, for every enrollment it's adding a new courseNode.

Been trying for many hours, and hope I can now get some advice that will point me in the correct direction. Thank you.

    private void updateJTree() {
    for (Category cat : catcontrol.getAllCategoriesList()) {

        category = new DefaultMutableTreeNode(cat);


        for (Course c : ccontrol.getAllCourses()) {

            if (cat.getIdCategory() == c.getIdCategory()) {
                for (Enrollment e : econtrol.getAllEnrollments()) {
                    if (e.getIdCourse() == c.getIdCourse()) {
                        if (cat.getIdCategory() == c.getIdCategory() && e.getCourse().equals(c)) {
                            root.add(category);
                        }

                        if (c.getIdCourse() == e.getIdCourse()) {

                            course = new DefaultMutableTreeNode(c);
                            category.add(course);
                            enrollment = new DefaultMutableTreeNode(e.getParticipant().getFirstNames());
                            course.add(enrollment);

                        }
                    }
                }
            }
        }
    }

    jTree1.setModel(new DefaultTreeModel(root));
    jTree1.addTreeSelectionListener(this);

    jTree1.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
}