public class JComboBoxExample {
  public static void main(String[] args) {
      List<Employee> employees = EmployeeDataAccess.getEmployees();
      JComboBox<Employee> comboBox = new JComboBox<>(employees.toArray(new Employee[employees.size()]));
      //renderer
      comboBox.setRenderer(new ExampleRenderer());
      //wrap in a panel
      JPanel panel = new JPanel();
      panel.add(comboBox);
      //frame
      JFrame frame = createFrame();
      frame.add(panel);
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
  }

  private static JFrame createFrame() {
      JFrame frame = new JFrame("JComboBox Example");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(new Dimension(600, 300));
      return frame;
  }
}