which I wrote from a book but when I run it, it shows exception
please give me the code to connect jlistbox to database when I click on btn1.
btn coding should search "name" in database and shows all the names in listbox

my coding:
here-- r1,r2,r3 are radio btns and l1,l2,l3 are labels, t1,t2 are textbox, listbox= toylist
String filter="";
if(r3.isSelected())
filter="where name='"+t1.getText()+"'";
else if (r1.isSelected())
{
float priceL= Float.parseFloat(t1.getText());
float priceF= Float.parseFloat(t2.getText());
filter="where price>="+priceL+"and price<="+priceF;
}
else if (r2.isSelected()){
int age=Integer.parseInt(t1.getText());
filter="where lowerlimit<="+age+"and upperlimit>="+age;
}
int count=0;
String query="select name from toys"+filter+";";
DefaultListModel model=new DefaultListModel();
try{
Class.forName("java.sql.Driver");
Connection con=DriverManager.getConnection("jdbc:my…
Statement stmt=con.createStatement();
ResultSet rs= stmt.executeQuery(query);
while(rs.next()){

String name=rs.getString("name");
model.addElement(name);
//model.add(count,rs.getString("name"));
count++;
}
toylist.setModel(model);
rs.close();
stmt.close();
con.close();
}
catch(Exception e){
JOptionPane.showMessageDialog(this,"Er… In Connectivity");
}