import java.awt.Dimension;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
public class Main {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
for (int i = 0; i < 30; i++) {
list.add("Hello, World " + i);
}
JScrollPane pane = new JScrollPane(new JList(list.toArray())) {
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 250);
}
};
JOptionPane.showMessageDialog(null, pane);
}
}