Java dependent JList

The given code display the names of the databases present in mysql database on a Jlist and when the user selects a particular database,the tables present under that database should be displayed on another Jlist.And finally display the column names present in the selected table on another jlist

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

public class JListExample extends JFrame{

JPanel panel = new JPanel();
public JListExample(){
panel.setLayout(null);
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/", "root", "root");
Statement st=con.createStatement();
ResultSet rs=st.executeQuery("show databases");
String data="";
while ( rs.next() ) {
data+= rs.getString("Database")+" "; 
}
String db[]=data.split(" ");
final JList list1=new JList(db);
JScrollPane pane1=new JScrollPane(list1);
final DefaultListModel model = new DefaultListModel();
final JList list2=new JList(model);
JScrollPane pane2=new JScrollPane(list2);
final DefaultListModel model2 = new DefaultListModel();
final JList list3=new JList(model2);
JScrollPane pane3=new JScrollPane(list3);
list1.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
if (!e.getValueIsAdjusting()) {
    model.clear();
String st = (String) list1.getSelectedValue();
System.out.println(st);
try{
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/"+st, "root", "root");
DatabaseMetaData meta = conn.getMetaData();
      ResultSet res = meta.getTables(null, null, "%", null);
      String tableNames = "";
      while (res.next()) {
      tableNames= res.getString(3)+" ";
      model.addElement(tableNames);
    }
}
catch(Exception ex){}
      }
   }
});
list2.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
if (!e.getValueIsAdjusting()) {
    model2.clear();
String str = (String) list2.getSelectedValue();
String s = (String) list1.getSelectedValue();
try{
    Connection conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/"+s, "root", "root");
    Statement stmt=conn.createStatement();
    ResultSet res = stmt.executeQuery("SELECT * FROM "+str+"");
        ResultSetMetaData md = res.getMetaData();
        int col = md.getColumnCount();
        for (int i = 1; i <= col; i++){
        String col_name = md.getColumnName(i);
        model2.addElement(col_name);
        }
}
catch(Exception ex){}
   }
 }
});
pane1.setBounds(10,10,100,100);
pane2.setBounds(120,10,100,100);
pane3.setBounds(230,10,100,100);
panel.add(pane1);
panel.add(pane2);
panel.add(pane3);
add(panel);
setSize(400,200);
setVisible(true);
}
catch(Exception e){}
}
public static void main(String[] args){
new JListExample();
}
}