New to Java

Hi Folks,

This is for a student database. When connecting to the database I am getting the foll error. The form for adding the students is not displaying. The following has part of the code. Can anybody help.

Thanks!

java.lang.NullPointerException
at MyPanel$1.actionPerformed(Student.java:256)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258
)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:234)
at java.awt.Component.processMouseEvent(Component.java:5488)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3093)
at java.awt.Component.processEvent(Component.java:5253)
at java.awt.Container.processEvent(Container.java:1966)
at java.awt.Component.dispatchEventImpl(Component.java:3955)
at java.awt.Container.dispatchEventImpl(Container.java:2024)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1766)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchyEventDispatchTh
read.java:234)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre
ad.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at MyPanel$1.actionPerformed(Student.java:276)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:18
49)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.jav
a:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258
)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonL
istener.java:234)
at java.awt.Component.processMouseEvent(Component.java:5488)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3093)
at java.awt.Component.processEvent(Component.java:5253)
at java.awt.Container.processEvent(Container.java:1966)
at java.awt.Component.dispatchEventImpl(Component.java:3955)
at java.awt.Container.dispatchEventImpl(Container.java:2024)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212
)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1766)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:234)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

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


public class Student extends JFrame
{
JTextArea out;
private JPanel panel1;
private JDesktopPane desktop;
private JTextArea queryoutput;
private ScrollingPanel scrollArea;
private String url;
private Connection connect, connection;
private JScrollPane textpane;





public Student()
{
super(" Student Database");

Container co = getContentPane();

scrollArea = new ScrollingPanel();
out = new JTextArea(6,30);
co.setLayout(new BorderLayout());
co.add(new JScrollPane(scrollArea), BorderLayout.CENTER);
textpane = new JScrollPane(out);
co.add(textpane, BorderLayout.SOUTH);




desktop = new JDesktopPane();
add(desktop);

JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic('F');

JMenuItem connectItem = new JMenuItem("Connect");
connectItem.setMnemonic('L');
fileMenu.add(connectItem);
connectItem.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)

{

JInternalFrame frame = new JInternalFrame("Login", true, true, true, true );

MyPanel panel = new MyPanel();

panel.setLayout(new GridLayout(4,2,5,5));

//panel.add(testlabel);

frame.add(panel);

desktop.add(frame);

frame.setSize(500, 200);

frame.setVisible(true);

}


}

);

fileMenu.addSeparator();
JMenuItem exititem = new JMenuItem("Exit");
exititem.setMnemonic('E');
fileMenu.add(exititem);

exititem.addActionListener(
new ActionListener()
{
public void actionPerformed (ActionEvent event)
{
System.exit(0);
}
}
);

JMenuBar bar = new JMenuBar();
setJMenuBar(bar);
bar.add(fileMenu);

queryoutput = new JTextArea(5,20);


JMenu dataMenu = new JMenu("Data");
dataMenu.setMnemonic('D');

JMenuItem queryItem = new JMenuItem("Query");
queryItem.setMnemonic('Q');
dataMenu.add(queryItem);
dataMenu.addSeparator();
queryItem.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
new DisplayQuery();
}
}
);
JMenuItem Addstud = new JMenuItem("Add Student");
Addstud.setMnemonic('A');
dataMenu.add(Addstud);
Addstud.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
new addstud(connection,scrollArea,out);
}
}
);
JMenuItem Delstud = new JMenuItem("Delete Student");
Delstud.setMnemonic('T');
dataMenu.add(Delstud);
Delstud.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
new Findrecord(connection, scrollArea, out);
new delstud(connection,scrollArea,out);
}
}
);

JMenuItem updatestud = new JMenuItem("Update Student");
updatestud.setMnemonic('U');
dataMenu.add(updatestud);
updatestud.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
new Findrecord(connection, scrollArea, out);
new UpdateStud(connection,scrollArea,out);
}
}
);

bar.add(dataMenu);

JMenu options = new JMenu("Options");
options.setMnemonic('O');

JMenuItem color = new JMenuItem("Color");
color.setMnemonic('C');
options.add(color);
color.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
ShowColor application = new ShowColor();
}
}
);

options.addSeparator();

JMenuItem font = new JMenuItem("Font");
font.setMnemonic('N');
options.add(font);
font.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{

new fonts();


}
}
);
bar.add(options);
setSize(500,500);
setVisible(true);
//show();

}

}

class MyPanel extends JPanel
{
private JLabel L1;
private JLabel L2;
private JLabel L3;
public JTextField userid;
public JPasswordField pw;
public JTextField database;
private JButton ok;
private Connection connect;
private JTextArea output;
private String url,URL;
String Userid;
String password;
String host;



public MyPanel()
{
L1 = new JLabel("User Id:");
add(L1);

userid = new JTextField(10);
add(userid);

L2 = new JLabel("Password:");
add(L2);

pw = new JPasswordField(10);
add(pw);

L3 = new JLabel("Database Name:");
add(L3);

database = new JTextField(10);
add(database);

ok = new JButton("OK");
add(ok);
ok.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
try
{
url = "jdbc:odbc:";

Userid = userid.getText();
password = pw.getText();
host = database.getText();
URL = url + host;


Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
connect = DriverManager.getConnection( URL, Userid, password );
output.append( "Connection successful\n" );
userid.setText("");
pw.setText("");
database.setText("");
}
catch ( ClassNotFoundException cnfex ) {
// process ClassNotFoundExceptions here
cnfex.printStackTrace();
output.append( "Connection unsuccessful\n" +
cnfex.toString() );
}
catch ( SQLException sqlex ) {
// process SQLExceptions here
sqlex.printStackTrace();
output.append( "Connection unsuccessful\n" +
sqlex.toString() );
}
catch ( Exception ex ) {
// process remaining Exceptions here
ex.printStackTrace();
output.append( ex.toString() );
}
}
}
);
}
}

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

public class ScrollingPanel extends JPanel
{
private JPanel lpanel, fpanel;
private String labels[] = {"Student ID:", "First Name:", "Last Name:", "Major:", "Age:"};

JTextField stuid, fname, lname, major, age;

public ScrollingPanel()
{
lpanel = new JPanel();
lpanel.setLayout( new GridLayout(labels.length,1));

//ImageIcon ii = new ImageIcon("images/icon.jpg");

for (int i = 0; i<labels.length; i++)
lpanel.add(new JLabel(labels,0));

fpanel = new JPanel();
fpanel.setLayout( new GridLayout(labels.length,1));
stuid = new JTextField(20);
fpanel.add(stuid);
fname = new JTextField(20);
fpanel.add(fname);
lname = new JTextField(20);
fpanel.add(lname);
major = new JTextField(20);
fpanel.add(major);
age = new JTextField(20);
fpanel.add(age);

setLayout(new GridLayout(1,2));
add(lpanel);
add(fpanel);
}
}