Make JComboBox to use the Custom Model in Java

 /*  w ww  .  j a va  2  s  .  c om*/
    
import javax.swing.AbstractListModel;
import javax.swing.ComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;

class MyComboBoxModel extends AbstractListModel implements ComboBoxModel {
  String[] ComputerComps = { "Monitor", "Key Board", "Mouse", "Joy Stick", "Modem", "CD ROM",
      "RAM Chip", "Diskette" };

  String selection = null;

  public Object getElementAt(int index) {
    return ComputerComps[index];
  }

  public int getSize() {
    return ComputerComps.length;
  }

  public void setSelectedItem(Object anItem) {
    selection = (String) anItem; // to select and register an
  } // item from the pull-down list

  // Methods implemented from the interface ComboBoxModel
  public Object getSelectedItem() {
    return selection; // to add the selection to the combo box
  }
}

public class Main {

  public static void main(String[] a){
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JComboBox cbox = new JComboBox(new MyComboBoxModel());  
    cbox.setMaximumRowCount(5);   
    frame.add(cbox);   
    
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}