Exception in thread-NullPointerException

Question

I am getting the following error. Trying to find where the mistake is. But not able to. Please help!!
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at addstud$1.actionPerformed(addstud.java:33)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:18
49)
at javax.swing.AbstractButton$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(EventDispatchTh
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)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
public class addstud
private ScrollingPanel fields;
private JTextArea output;
private Connection connection;
private JInternalFrame frame;
public addstud(Connection c, ScrollingPanel f, JTextArea o, JInternalFrame F)
     connection = c;
     fields = f;
     output = o;
     frame = F;
     JButton ADD = new JButton("Add Student");
     frame.add(ADD, BorderLayout.SOUTH);
     ADD.addActionListener(
     new ActionListener()
     public void actionPerformed(ActionEvent event)
     try
     Statement statement = connection.createStatement(); Line 33
     new Clearfields(fields);
     if(!fields.lname.getText().equals("") && !fields.fname.getText().equals(""))
     String query = "INSERT INTO Student (" +
     "studentid, fisrtname, lastname, Major, Age" +
     ") VALUES ('"+
     fields.stuid.getText() + "', '"+
     fields.fname.getText() + "', '"+
     fields.lname.getText() + "', '"+
     fields.major.getText() + "', '"+
     fields.age.getText() + "')";
     output.append("\nSending query: " +
               connection.nativeSQL( query )
               + "\n");
     int result = statement.executeUpdate(query);
     if (result == 1)
     output.append("\nInsertion successful\n");
     else
          output.append("\nInsertion failed\n");
          fields.stuid.setText("");
          fields.fname.setText("");
          fields.lname.setText("");
          fields.major.setText("");
          fields.age.setText("");
     else
     output.append("\n Enter the student details and press Add Student\n");
     statement.close();
     catch(SQLException sqlex)
     sqlex.printStackTrace();
     output.append(sqlex.toString());
Progam where addstud is called
import javax.swing.*;
import java.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JColorChooser.*;
public class Student extends JFrame
     public JTextArea out;
     private JPanel panel1;
     private JDesktopPane desktop;
     private JTextArea queryoutput;
     public ScrollingPanel scrollArea;
     private String url;
     //private Connection connect, connection;
     public JScrollPane textpane;
     public JTextField userid;
     public JPasswordField pw;
     public JTextField database;
     Color current_color = Color.LIGHT_GRAY;
     private JPanel radiopanel;
     private JPanel panel;
     private JLabel f1;
     public JRadioButton font1;
     public JRadioButton font2;
     Font current_Font;
     MyPanel p = new MyPanel();
     Connection connection = p.getConnection();
     //public Color current_color = Color.LIGHT_GREY;
     public Student()
          super(" Student Database");
          final Container co = getContentPane();
          scrollArea = new ScrollingPanel(current_color, current_Font);
          out = new JTextArea(6,30);
          out.setBackground(current_color);
          //out.setFont(current_Font);
          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(current_color, current_Font);
                    //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);
                    connection = panel.getConnection();
          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);
                         //connection.close();
                         out.setText("Connection closed\n");
          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);
          connection = p.getConnection();
          Addstud.addActionListener(
               new ActionListener()
                    public void actionPerformed(ActionEvent event)
                    JInternalFrame frame = new JInternalFrame("Add Student", true, true, true, true );
                    //MyPanel1 panel = new MyPanel1(current_color);
                    ScrollingPanel panel = new ScrollingPanel(current_color, current_Font);
                    frame.add(panel);
                    desktop.add(frame);
                    frame.setSize(500, 300);
                    frame.setVisible(true);
                    connection = p.getConnection();
                    new addstud(connection,scrollArea,out,frame);
                         );          JMenuItem Delstud = new JMenuItem("Delete Student");
          Delstud.setMnemonic('T');
          dataMenu.add(Delstud);
          Delstud.addActionListener(
               new ActionListener()
                    public void actionPerformed(ActionEvent event)
                    JInternalFrame frame = new JInternalFrame("Delete Student", true, true, true, true );
                    //MyPanel1 panel = new MyPanel1(current_color);
                    ScrollingPanel panel = new ScrollingPanel(current_color, current_Font);
                    frame.add(panel);
                    desktop.add(frame);
                    frame.setSize(500, 400);
                    frame.setVisible(true);
                    connection = p.getConnection();
                    new delstud(connection,scrollArea,out,frame);
          JMenuItem updatestud = new JMenuItem("Update Student");
          updatestud.setMnemonic('U');
          dataMenu.add(updatestud);
          updatestud.addActionListener(
               new ActionListener()
                    public void actionPerformed(ActionEvent event)
                    JInternalFrame frame = new JInternalFrame("Update Student", true, true, true, true );
                    ScrollingPanel panel = new ScrollingPanel(current_color, current_Font);
                    frame.add(panel);
                    desktop.add(frame);
                    frame.setSize(500, 400);
                    frame.setVisible(true);
                    connection = p.getConnection();
                    new UpdateStud(connection,scrollArea,out,frame);
          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)
                    JInternalFrame frame = new JInternalFrame("Select Color", true, true, true, true );
                    JPanel panel = new JPanel();
                    //panel.setLayout(BorderLayout);
                    JButton change_color = new JButton("Change Color");
                    frame.add(change_color, BorderLayout.SOUTH);
                    change_color.addActionListener(
                    new ActionListener()
                    public void actionPerformed(ActionEvent event)
                    JInternalFrame frame = new JInternalFrame("Select a Color", true, true, true, true );
                    current_color = JColorChooser.showDialog( null, "Select a Color", current_color);                    
                    //frame.add(color);
                    out.setBackground(current_color);
                    if (current_color == null)
                    current_color = Color.LIGHT_GRAY;
                    desktop.add(frame);
                    frame.setSize(500, 400);
                    frame.setVisible(true);
                    frame.add(panel);
                    desktop.add(frame);
                    frame.setSize(500, 400);
                    frame.setVisible(true);
          options.addSeparator();
          JMenuItem font = new JMenuItem("Font");
          font.setMnemonic('N');
          options.add(font);
          font.addActionListener(
               new ActionListener()
                    public void actionPerformed(ActionEvent event)
                    JInternalFrame frame = new JInternalFrame("Select Font", true, true, true, true );
                    radiopanel = new JPanel();
                    panel = new JPanel();
                    radiopanel.setLayout(new GridLayout(3,1,5,5));
                    font1 = new JRadioButton("Times Roman", true);
                    font2 = new JRadioButton("Courier", false);
                    radiopanel.add(font1);
                    radiopanel.add(font2);
                    ButtonGroup radiogroup = new ButtonGroup();
                    radiogroup.add(font1);
                    radiogroup.add(font2);
                    add(radiopanel, BorderLayout.CENTER);
                    //setSize (500, 300);
                    //setVisible(true);
                    JButton change_font = new JButton("Change Font");
                    frame.add(change_font, BorderLayout.SOUTH);
                    change_font.addActionListener(
                    new ActionListener()
                         public void actionPerformed(ActionEvent event)
                         if(font1.isSelected())
                         current_Font = new Font("Times-Roman", Font.BOLD, 12);
                         if(font2.isSelected())
                         current_Font = new Font("Courier", Font.BOLD, 12);;                         
                         out.setFont(current_Font);
                    frame.add(radiopanel);
                    desktop.add(frame);
                    frame.setSize(300, 300);
                    frame.setVisible(true);
          bar.add(options);
          setSize(500,500);
          setVisible(true);
          //show();
class MyPanel extends JPanel
          private JLabel L1;
          private JLabel L2;
          private JLabel L3;
          private JButton ok;
          private Connection connection;
          private JTextArea output;
          private String url,URL;
          String Userid;
          String password;
          String host;
// Color cur_color;
          public MyPanel()
               super();
     public MyPanel(Color x, Font f)
Color cur_color = x;
          Font cur_font = f;
          L1 = new JLabel("User Id:");
          add(L1);
          userid = new JTextField(10);
          add(userid);
          userid.setBackground(x);
          userid.setFont(f);
          L2 = new JLabel("Password:");
          add(L2);
          pw = new JPasswordField(10);
          add(pw);
          pw.setBackground(x);
          pw.setFont(f);
          L3 = new JLabel("Database Name:");
          add(L3);
          database = new JTextField(10);
          add(database);
          database.setBackground(x);
          database.setFont(f);
          ok = new JButton("OK");
          add(ok);
          ok.addActionListener(     
          new ActionListener()
          public void actionPerformed(ActionEvent event)
          try
     url = "jdbc:odbc:";
          Userid = userid.getText();
          password = new String ( pw.getPassword() );
          host = database.getText();
          URL = url + host;
     Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
     connection = DriverManager.getConnection( URL, Userid, password );
     out.append( "Connection successful\n" );
          catch ( ClassNotFoundException cnfex ) {     
     // process ClassNotFoundExceptions here
     cnfex.printStackTrace();     
     out.append( "Connection unsuccessful\n" +
cnfex.toString() );
     catch ( SQLException sqlex ) {
     // process SQLExceptions here
     sqlex.printStackTrace();
     out.append( "Connection unsuccessful\n" +
sqlex.toString() );
     catch ( Exception ex ) {
     // process remaining Exceptions here
     ex.printStackTrace();
     out.append( ex.toString() );
          public Connection getConnection()
               return connection;
}

Answer 1

Thanks!!
I had 2 var and that created the problem
In the code below Is the insert statement correct cos it is not inserting into the table. it prints this statement always
output.append("\n Enter the student details and press Add Student\n");
if(!fields.stuid.getText().equals("") )
     String query = "INSERT INTO Student (" +
     "studentid, fisrtname, lastname, Major, Age" +
     ") VALUES ('"+
     fields.stuid.getText() + "', '"+
     fields.fname.getText() + "', '"+
     fields.lname.getText() + "', '"+
     fields.major.getText() + "', '"+
     fields.age.getText() + "')";
     output.append("\nSending query: " +
               connection.nativeSQL( query )
               + "\n");
     int result = statement.executeUpdate(query);
     if (result == 1)
     output.append("\nInsertion successful\n");
     else
          output.append("\nInsertion failed\n");
          fields.stuid.setText("");
          fields.fname.setText("");
          fields.lname.setText("");
          fields.major.setText("");
          fields.age.setText("");
     else
     output.append("\n Enter the student details and press Add Student\n");