Why did exception...?

Question

I have copied this program from "Java online Training":
import java.awt.Color;
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
import java.net.*;
import java.util.*;
import java.io.*;
class Dba extends JFrame implements ActionListener {
JLabel text, clicked;
JButton button, clickButton;
JPanel panel;
JTextField textField;
private boolean _clickMeMode = true;
private Connection c;
final static private String _driver = "sun.jdbc.odbc.JdbcOdbcDriver";
final static private String _url = "jdbc:odbc:dba";
Dba(){ //Begin Constructor
text = new JLabel("Text to save to database:");
button = new JButton("Click Me");
button.addActionListener(this);
textField = new JTextField(20);
panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.setBackground(Color.white);
getContentPane().add(panel);
panel.add(BorderLayout.NORTH, text);
panel.add(BorderLayout.CENTER, textField);
panel.add(BorderLayout.SOUTH, button);
} //End Constructor
public void actionPerformed(ActionEvent event){
try{
// Load the Driver
Class.forName (_driver);
// Make Connection
c = DriverManager.getConnection(_url);
catch (java.lang.ClassNotFoundException e){
System.out.println("Cannot find driver class");
System.exit(1);
}catch (java.sql.SQLException e){
System.out.println("Cannot get connection");
System.exit(1);
Object source = event.getSource();
if(source == button){
if(_clickMeMode){
JTextArea displayText = new JTextArea();
try{
//Code to write to database
String theText = textField.getText();
Statement stmt = c.createStatement();//This is here Exception appears but I don't know why
String updateString = "INSERT INTO dba VALUES ('" + theText + "')";
int count = stmt.executeUpdate(updateString);//may be exception also appeared here
//Code to read from database
ResultSet results = stmt.executeQuery("SELECT TEXT FROM dba ");
while(results.next()){
String s = results.getString("TEXT");
displayText.append(s + "\n");
stmt.close();
}catch(java.sql.SQLException e){
System.out.println("Cannot create SQL statement");
//Display text read from database
text.setText("Text retrieved from database:");
button.setText("Click Again");
_clickMeMode = false;
//Display text read from database
} else {
text.setText("Text to save to database:");
textField.setText("");
button.setText("Click Me");
_clickMeMode = true;
public static void main(String[] args){
Dba frame = new Dba();
frame.setTitle("Example");
WindowListener l = new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
frame.addWindowListener(l);
frame.pack();
frame.setVisible(true);
After I compiled this program and I run it,when I clicked on the button "Click Me" there was an Exception("Cannot create SQL statement").I don'nt know why.Please explain for me.Thank a lot!

Answer 1

Try actually finding out what SQLException was thrown. In the catch block where you're printing "Cannot create SQL statement", add another print statement below it.
System.out.println(e.getMessage());
This will tell you exactly what kind of SQL exception you are getting.