Event Problem?

[Peter Phung]

I'm having some difficulty with an application that i'm writing.
It's a tool to query a database. When the application is started everything appears to run fine. But the application only lets the user run one query.
i.e. after the first query the GUI stops working and doesn't let me click any buttons.
Can anyone help me?
Here's some of the code, i've tried to post what i think are relevant parts. if anyone needs to see more code let me know and i'll post it :

 
private void jbInit() throws Exception  {
this.getContentPane().setLayout(gridBagLayout1);
this.setSize(new Dimension(800, 450));
menuFile.setText("File");
menuHelp.setText("Help");
menuHelpAbout.setText("About");
menuHelpAbout.addActionListener(new ActionListener()  {
public void actionPerformed(ActionEvent e) {
    helpAbout_actionPerformed(e);
}
    });
MI_Exit.setText("Exit");
MI_Exit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(ActionEvent e) {
    MI_Exit_actionPerformed(e);
}
    });
//Other menu items and listeners
this.getContentPane().add(lSelection, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0,
GridBagConstraints.EAST, GridBagConstraints.BOTH, new Insets(5, 15, 5, 5), 0, 0));
//More constraints
this.getContentPane().setBackground(Color.white);
this.getContentPane().setForeground(maroon);
//
// We try to connect to the underlying database for
// defining choice items
//
if (!loadDBDriver())
    System.exit(0);
if (!getDBConnection())
    System.exit(0);
//
// We update the choice items
//
if (!updateChoiceItems())
    System.exit(0);

}
 

I would be grateful for any help

[Younes Essouabni]

Can you explain (or post the code) what those methods does?
if (!loadDBDriver()) System.exit(0);if (!getDBConnection()) System.exit(0);//// We update the choice items//if (!updateChoiceItems()) System.exit(0);

[Peter Phung]

the methods loadDBDriver and getDBConnection try to load the database driver and connect to the database or exit from the system.
updateChoiceItems loads records from the database into a choice button in the GUI.
I don't think that these methods are the problem. The problem i'm having is really weird
i hope that explains the methods.
If necessary i will post the code

[Peter Phung]

Here's the methods anyway

  //======================================================================
    // We try to load the database driver
    // input: -
    // output:
    // boolean error - OK true / NOK false
    //======================================================================
    boolean loadDBDriver() {
try {
    // The newInstance call is a workaround for some
    // broken Java implementations
    Class.forName("org.gjt.mm.mysql.Driver").newInstance();
} catch (Exception E) {
    JOptionPane.showMessageDialog(this,"*** Error ***\nCouldn't load Database Driver - I quit");
    return false;
}
return true;
    }
    //======================================================================
    // We try to connect to the database now
    // input: -
    // output:
    //  boolean error - OK true / NOK false
    //======================================================================
    boolean getDBConnection () {
String connectionStr = "jdbc:mysql://"+db_host+"/"
    +db_Database+"?user="+db_user+"&password="+db_passwd;
// System.out.println(connectionStr);
try {
    connection = DriverManager.getConnection(connectionStr);
} catch (SQLException E) {
    JOptionPane.showMessageDialog(this,"*** Error ***\nCouldn't connect to database - I quit");
    System.out.println("SQLException: "+E.getMessage());
    System.out.println("SQLState    : "+E.getSQLState());
    System.out.println("VendorError : "+E.getErrorCode());
    return false;
}
return true;
    }
    //======================================================================
    // We try to update the PDP choice button items
    // input: -
    // output:
    //  boolean error - OK true / NOK false
    //======================================================================
    boolean  updatePDPChoiceItems() {
try {
    Statement stmt = connection.createStatement();
    ResultSet rset;
    
    // We also update the Choice Button with possible PDP Numbers
    String strcust = chCustomer.getSelectedItem();
    String queryStr = "SELECT Projects.CustomerID, Projects.PDP"+
" FROM (Projects LEFT JOIN Customer ON Projects.CustomerID=Customer.ID) WHERE Name LIKE '"+strcust+"' ORDER BY PDP";
    rset = stmt.executeQuery(queryStr);
    tfPDPNo.setText("");
    chPDPNo.removeAll();
    while (rset.next()) {
chPDPNo.add(rset.getString("PDP"));
    }
} catch (SQLException E) {
    JOptionPane.showMessageDialog(this,"*** Error ***\nSQL Query Error - I quit");
    System.out.println("SQLException: "+E.getMessage());
    System.out.println("SQLState    : "+E.getSQLState());
    System.out.println("VendorError : "+E.getErrorCode());
    return false;
}
return true;
    }