Swing Java Tutorial

By default, every JList component is in multiple-selection mode.
ModeDescription
ListSelectionModel.SINGLE_SELECTIONOne item at a time can be selected.
ListSelectionModel.SINGLE_INTERVAL_SELECTIONOne contiguous range of items can be selected.
ListSelectionModel.MULTIPLE_INTERVAL_SELECTIONAny set of ranges can be selected.

import java.awt.BorderLayout;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
public class SelectionModeDemo {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Sizing Samples");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    DefaultListModel model = new DefaultListModel();
    model.ensureCapacity(100);
    for (int i = 0; i < 100; i++) {
      model.addElement(Integer.toString(i));
    }
    JList jlist2 = new JList(model);
    jlist2.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION );
    
    JScrollPane scrollPane2 = new JScrollPane(jlist2);
    frame.add(scrollPane2, BorderLayout.CENTER);
    frame.setSize(300, 350);
    frame.setVisible(true);
  }
}