Clear Button Java Wont Work

[Ty44ler]

Im writing a Java program for a hospital billing system. Basically when a user enters information in my text fields I want them to be able to click a clear button and clear all of their entered information. However, my clear button wont work, but it doesn't give me errors when Im writing the code (I use JBuilder to write). When I click the clear button it doesnt clear and gives this:

Quote:

xception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Primatech$ClearListener.actionPerformed(Primatech. java:231)
at javax.swing.AbstractButton.fireActionPerformed(Abs tractButton.java:1849)
at javax.swing.AbstractButton$Handler.actionPerformed (AbstractButton.java:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed (DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultB uttonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.jav a:5488)
at javax.swing.JComponent.processMouseEvent(JComponen t.java:3126)
at java.awt.Component.processEvent(Component.java:525 3)
at java.awt.Container.processEvent(Container.java:196 6)
at java.awt.Component.dispatchEventImpl(Component.jav a:3955)
at java.awt.Container.dispatchEventImpl(Container.jav a:2024)
at java.awt.Component.dispatchEvent(Component.java:38 03)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4212)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:3892)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:3822)
at java.awt.Container.dispatchEventImpl(Container.jav a:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1778 )
at java.awt.Component.dispatchEvent(Component.java:38 03)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 463)
at java.awt.EventDispatchThread.pumpOneEventForHierar chy(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:157)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:149)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:110)

Here's My Code:

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


public class Primatech extends  JFrame {
	
	  JTextField jtxtFirst;
	  JButton jbtClear;
	  
	  /** Main method */
	  public static void main(String[] args) {
	    Primatech frame = new Primatech();
	    frame.setTitle("Primatech Health Services");
	    frame.setLocationRelativeTo(null);
	    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	    frame.setSize(600, 420);
	    frame.setVisible(true);
	    }		

  public Primatech()
  {

    Container c = getContentPane();
    //-----------------ATTRIBUTES----------------------------
    // Set GridLayout, 5 rows, 3 columns, and gaps 3 between
    c.setLayout(new BorderLayout(1, 1));

    //Colors for Program
    Color c1 = new Color(000, 000, 000);
    Color c2 = new Color(234, 234, 230);
    Color c3 = new Color(255, 255, 204);

    //Set Fonts for Program
    Font serifFont = new Font( "Sans_Serif", Font.BOLD, 12 );
    Font titleFont = new Font ( "Serif", Font.BOLD, 26);
    
    //Declared JPanels
    JPanel jpLabels = new JPanel();
    JPanel jpTextFields = new JPanel();
    JPanel jpCB = new JPanel();
    JPanel jpInfo = new JPanel();
    JPanel jpPay = new JPanel();
    JPanel jpButtons = new JPanel();
    JPanel jpBillArea = new JPanel();
    JPanel jpMenu = new JPanel();
    
    
    //Declare Borders
    Border rBB= new TitledBorder( "Payment Type" );
    Border rTF= new TitledBorder ( "Patient Information");
    Border rPB= new TitledBorder ( "Patient Bill");

    //-----------------MENU BAR----------------------------
    JMenuBar newBar = new JMenuBar();

    //Adding Help to Menu Bar
    JMenu helpMenu = new JMenu("Help");
    newBar.add(helpMenu);
    helpMenu.add(new JMenuItem("1-800-HELPMEE"));
    helpMenu.add(new JMenuItem("www.btvs.com/techsupp"));

    //Declare Title Primatech Services
    JLabel titleLabel = new JLabel("Primatech Services");
    titleLabel.setFont( titleFont);

    //Create Image Icon
    ImageIcon aPlus = new ImageIcon("grdaplus.jpg");
    JLabel jlblA = new JLabel(aPlus);
    
    jpMenu.setLayout(new BorderLayout());
    jpMenu.setBackground( c3 );
    jpMenu.add(jlblA, BorderLayout.EAST);
    jpMenu.add(titleLabel, BorderLayout.WEST);
    jpMenu.add(newBar, BorderLayout.NORTH);
    
    //-----------------COMBO BOX----------------------------
    //Array of States and Doctors for Combo Box
    String states[] = { "State:", "GA", "FL", "CO", "NM","OH", "MI", "NY", "PA","MA", "HW" };
    String doctor[] = { "Doctor:", "Sylar", "Suresh"};

    //Combo Box
    JComboBox jcombo1 = new JComboBox(states);
    jcombo1.setBackground( c3 );
    JComboBox jcombo2 = new JComboBox(doctor);
    jcombo2.setBackground( c3 );

    //Area to Display Patient Info
    jpBillArea.setLayout(new BorderLayout());
    JTextArea billArea = new JTextArea(10, 10);
    jpBillArea.setBackground( c3 );
    jpBillArea.add(billArea);
    
    //-----------------CHECK BOXES----------------------------
    //Check Box
    jpCB.setLayout(new BorderLayout());
    JCheckBox jcb1 = new JCheckBox("Payment Received?");
    jcb1.setBackground( c3 );
    JCheckBox jcb2 = new JCheckBox("Insure Claim Filed?");
    jcb2.setBackground( c3 );
    jpCB.add(jcb1, BorderLayout.EAST);
    jpCB.add(jcb2, BorderLayout.WEST);

    //-----------------RADIO BUTTONS----------------------------
    //Declare Radio Buttons
    JRadioButton jrb1 = new JRadioButton("Cash");
    JRadioButton jrb2 = new JRadioButton("Check");
    JRadioButton jrb3 = new JRadioButton("Credit Card");

    //Create JPanel with Radio buttons added
    JPanel jpRadioButtons = new JPanel();
    jpRadioButtons.setBorder(rBB);
    jpRadioButtons.setLayout(new BorderLayout(3,1));
    jpRadioButtons.setBackground( c3 );
    jpRadioButtons.add(jrb1 = new JRadioButton("Cash"), BorderLayout.EAST);
    jpRadioButtons.add(jrb2 = new JRadioButton("Check"), BorderLayout.WEST);
    jpRadioButtons.add(jrb3 = new JRadioButton("Credit Card"), BorderLayout.CENTER); 

    //Set BG color for radio Buttons
    jrb1.setBackground( c3 );
    jrb2.setBackground( c3 );
    jrb3.setBackground( c3 );

    //Create Group of Radio Buttons
    ButtonGroup btg = new ButtonGroup();
    btg.add(jrb1);
    btg.add(jrb2);
    btg.add(jrb3);
    
    //-----------------LABELS----------------------------
    JLabel jlblFirst = new JLabel("First Name:");
    JLabel jlblLast = new JLabel("Last Name:");
    JLabel jlblAddress = new JLabel("Address:");
    JLabel jlblCity = new JLabel("City:");
    JLabel jlblState = new JLabel("State:");
    JLabel jlblZip = new JLabel("Zip Code:");
    JLabel jlblSSN = new JLabel("SSN:");
    JLabel jlblDoctor = new JLabel("Doctor Name:");
    JLabel jlblApp = new JLabel("Appointment Date:");
    
    //Add Jlabels to JLabels Panel
    jpLabels.setLayout(new GridLayout(9, 1));
    jpLabels.setBackground( c3 );
    jpLabels.add(jlblFirst);
    jpLabels.add(jlblLast);
    jpLabels.add(jlblAddress);
    jpLabels.add(jlblCity);
    jpLabels.add(jlblState);
    jpLabels.add(jlblZip);
    jpLabels.add(jlblSSN);
    jpLabels.add(jlblDoctor);
    jpLabels.add(jlblApp);
    
    //-----------------TEXT FIELDS----------------------------  
    //Declare Text Fields
    JTextField jtxtFirst = new JTextField("First Name");
    JTextField jtxtLast = new JTextField("", 15);
    JTextField jtxtAddress = new JTextField("", 15);
    JTextField jtxtCity = new JTextField("", 15);
    JTextField jtxtZip = new JTextField("", 15);
    JTextField jtxtSSN = new JTextField("", 15);
    JTextField jtxtApp = new JTextField("", 15);
    
    jpTextFields.setLayout(new GridLayout(9, 1));
    jpTextFields.setBackground( c3 );
    jpTextFields.add(jtxtFirst);
    jpTextFields.add(jtxtLast);
    jpTextFields.add(jtxtAddress);
    jpTextFields.add(jtxtCity);
    jpTextFields.add(jcombo1);
    jpTextFields.add(jtxtZip);
    jpTextFields.add(jtxtSSN);
    jpTextFields.add(jcombo2);
    jpTextFields.add(jtxtApp);


    jpInfo.setLayout(new BorderLayout());
    jpInfo.setBorder(rTF);
    jpInfo.setBackground( c3 );
    jpInfo.add(jpLabels, BorderLayout.WEST);
    jpInfo.add(jpTextFields, BorderLayout.EAST);
    
    //----------------BUTTONS----------------------------
    //Display Bill Button
    JButton jbt1 = new JButton("Display Bill");
    jbt1.setBackground( c2 );
    jbt1.setForeground( c1 );
    jbt1.setFont( serifFont );

    //Clear Bill Button
    JButton jbtClear = new JButton("Clear Bill");
    jbtClear.setBackground( c2 );
    jbtClear.setForeground( c1 );
    jbtClear.setFont( serifFont );
 
    
    jpButtons.setLayout(new FlowLayout());
    jpButtons.setBackground( c3 );
    jpButtons.add(jbt1);
    jpButtons.add(jbtClear);
    jbtClear.addActionListener( new ClearListener() );
    
    jpPay.setLayout(new BorderLayout());
    jpPay.setBackground( c3 );
    jpPay.setBorder(rPB);
    jpPay.add(jpRadioButtons, BorderLayout.SOUTH);
    jpPay.add(jpCB, BorderLayout.CENTER);
    jpPay.add(billArea, BorderLayout.NORTH);
    
    //-----------------FRAME----------------------------
    // Add labels and text fields to the frame
    c.setBackground( c3 );
    add (jpMenu, BorderLayout.NORTH);
    add (jpInfo, BorderLayout.WEST);
    add (jpPay, BorderLayout.EAST);
    add (jpButtons, BorderLayout.SOUTH);
    
  }
  
  private class ClearListener implements ActionListener {
	    public void actionPerformed(ActionEvent e) {
	      jtxtFirst.setText("");
	    } // end actionPerformed

	  }// end ClearListener class

 }

The first name text field should be the only one that works, didnt want to write it out for all of them...

Any suggestions?

[Rootstonian]

Not that familiar with JAVA, but this line may be your problem...(just a WAG "wild a$$ guess)

jbtClear.addActionListener( new ClearListener() );

I say that due to the first line of your error message "....Null pointer exception..."

Can you set a "debug" mode and step through the program?

Or maybe ClearListener needs to return a value???

[Ty44ler]

Hmmm...

Well as a WAT (wild a$$ try)

I gave the ClearListener a value of: jtxtFirst.setText("")

however that didnt work and I get the same thing...

[sr71000]

try commenting out this line

jtxtFirst.setText("");

replace it with a print out to the console. see if jtxtFirst is null.

[Ty44ler]

I finally got it to work.

As what was stated before I didnt need to declare it a second time. Thank you for your help!

[sandesh007]

sandesh nawadkar:- I sujjest you that you have to use getContentPane().add() method

[sandesh007]

use jCreator or kava pro that will help u to remove errors.