NullPointerException

[Al Wells]

I just seem to be having all kinds of problems. But, I am having fun...

I am getting a NullPointerException when I compile this. Given my greenhorn status (ignore the moniker to the left), I can't figure out why. I have declared and caught the exception. What do I have to do and how do I have to do it to get this exception to go away?

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

public class TestLogin extends JFrame{
public static void main (String [] args) {

new TestLogin();

}// close main
 
private Connection Database;
private String uNameString = "test";
private String pWordString = "test";
private JButton logButton;
 
public TestLogin() {

String URL = "jdbc  :-o	  dbc:SMLocalData";
String userID = "null";
String password = "null";
Statement DataRequest;
ResultSet Results;

try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Database = DriverManager.getConnection(URL, userID, password);
}//close try

catch (ClassNotFoundException error) {

JOptionPane.showMessageDialog (TestLogin.this, "Unable to load ODBC/JDBC bridge.", "Data Access Denied", JOptionPane.INFORMATION_MESSAGE);
System.exit(1);

}//close catch

catch (SQLException error) {
JOptionPane.showMessageDialog(TestLogin.this, "Unable to connect to the database.", "Data Access Denied", JOptionPane.INFORMATION_MESSAGE);
System.exit(2);

}//close catch

// Try to query user name and password
try {
String query = "SELECT FirstName, "+
"LastName FROM CUS_User " +
"WHERE EmailAddress = '" + uNameString +
"' AND Password = '" + pWordString +"'";
DataRequest = Database.createStatement();
Results = DataRequest.executeQuery(query);
DisplayResults(Results);
DataRequest.close();
}//close try
 
catch (SQLException error) {

JOptionPane.showMessageDialog(TestLogin.this,"Unable to execute query.", "Query Error", JOptionPane.INFORMATION_MESSAGE);
System.exit(3);

}//close catch

}//close constructor

private void DisplayResults(ResultSet DisplayResults) throws SQLException {

try {
boolean Records = DisplayResults.next();

if(!Records) {
JOptionPane.showMessageDialog (this, "No User Found");
setTitle("Try Again");
return;
}// close try

String FirstName = new String();
String LastName = new String();

FirstName = DisplayResults.getString(1);
LastName = DisplayResults.getString(2);

JPanel logPanel = new JPanel();
JLabel firstLabel = new JLabel(FirstName);
JLabel lastLabel = new JLabel(LastName);

//create new action object here

logPanel.add(firstLabel);
logPanel.add(lastLabel);
logPanel.add(logButton);

this.setSize(450,450);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.add(logPanel);
this.setLocationRelativeTo(null);
this.setVisible(true);

}//close try

catch (SQLException error) {
JOptionPane.showMessageDialog(this, "No User Found", "Log In Failed", JOptionPane.INFORMATION_MESSAGE);
System.exit(3);

}//close catch

}// close method

}//close class
 

[ May 23, 2005: Message edited by: Al Wells ]

[Al Wells]

Never mind... I did not create a new button. Figured it out due to my handy Java In A Nutshell reference book.

[Jeff Grant]

In the future, would have helped to print your stack trace so we could see exactly where the error was coming from.

[Al Wells]

Jeff,

I will try that. I am still learning and appreciate the feedback that will help me be helped. Thanks for the info.

Cheers,
Al