import java.awt.FlowLayout;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JFrame;

public class NonStringListCase {
	private static class Stringable {
		private String essence;
		Stringable() { this.essence = "null";  }
		Stringable(String s) { this.essence = s; }
		public String toString() { return essence; }
	}

	public static void main(String[] argv) {
		JList jlString = new JList(new String[]{"String 1", "String 2"});
		JList jcbObject = new JList(new Stringable[]{new Stringable(), new Stringable("another one")});
		JList jcbMix = new JList(new Object[]{"String 1", new Stringable("another one")});

		JPanel jp = new JPanel();
		jp.setLayout(new FlowLayout());
		jp.add(jlString);
		jp.add(jcbObject);
		jp.add(jcbMix);

		JFrame frame = new JFrame("Test");
		frame.setContentPane(jp);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
}