Test case:

import javax.swing.*;
import java.awt.*;

public class testlist
{
        public static void main(String[] args)
        {
                JFrame f = new JFrame();

                DefaultListModel v = new DefaultListModel();
                v.addElement("alsdkfj");
                v.addElement("lasdkfj");
                v.addElement("owieur");
                v.addElement("weoiru");
                v.addElement("lskdfj");
                v.addElement("zcxvn");
                v.addElement("zxcvlkzvm");



                JList a = new JList(v);
                a.setVisibleRowCount(2);
                JScrollPane p = new JScrollPane(a);

                a.setLayoutOrientation(JList.HORIZONTAL_WRAP);


                f.getContentPane().add(p);
                f.pack();
                f.show();

        }
}

The items in the list should be wrapped vertically, not horizontally.