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Java Swing jLabel java.lang.NullPointerException [duplicate]

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What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 2 years ago.
I have a class Hangman and one class GUI. Hangman class for the process. So, I want to passing the value String form Hangman class to jLabel in GUI. When I run the project and I am strungling in java.lang.NullPointerException even I wrote the right code. When user click start. The value from class Hangman will show to the jLabel
Hangman class
package hangman;
import java.util.*;
import java.io.*;
import java.awt.*;
public class Hangman {
String filename = "words.txt";
String[] wordList;
String[] wordBanks = {"DISAVOW","KEYHOLE","QUIZZES",
"WHOMEVER","ZIGZIG","WHEEZY","UNWORTHY",
"WHIZZING","JOCKEY","MICROWAVE"};
String[] answer;
int index;
String[] resultarray;
StringBuilder stringbuilder = new StringBuilder();
String resultstring;
public Hangman()
{
initialComponent();
}
public void initialComponent()
{
index = randomIndex();
answer = wordBanks[index].split("");
resultarray = new String[answer.length];
for(int i = 0; i < answer.length ;i++)
{
resultarray[i] = " _ ";
stringbuilder.append(resultarray[i]);
}
resultstring = stringbuilder.toString();
}
public int randomIndex()
{
int rand = 0;
// define the range
int max = 10;
int min = 0;
int range = max - min;
// generate random numbers within 1 to 10
for (int i = 0; i < 10; i++) {
rand = (int)(Math.random() * range) + min;
// Output is different everytime this code is executed
//System.out.println(rand);
}
return rand;
}
public void printWord()
{
System.out.println(wordBanks[randomIndex()].toString() + "|" + wordBanks[randomIndex()].length());
}
public void initialWord()
{
int random = randomIndex();
//answer = new String[random];
answer = wordBanks[random].split("");
for (int i = 0; i < answer.length;i++)
System.out.println(answer[i]);
}
public static void main(String[] args) {
// TODO code application logic here
Hangman hangman = new Hangman();
GUI gui = new GUI();
gui.setVisible(true);
}
}
GUI class
'''
package hangman;
public class GUI extends javax.swing.JFrame {
Hangman hangman;
/**
* Creates new form GUI
*/
public GUI() {
initComponents();
//defaultResult();
}
public void defaultResult()
{
jLabelGuess.setText(hangman.resultstring);
}
#SuppressWarnings("unchecked")
private void initComponents() {
jFrame1 = new javax.swing.JFrame();
jLabel1 = new javax.swing.JLabel();
jButtonStart = new javax.swing.JButton();
jButtonA = new javax.swing.JButton();
jButtonB = new javax.swing.JButton();
jButtonC = new javax.swing.JButton();
jButtonD = new javax.swing.JButton();
jButtonE = new javax.swing.JButton();
jButtonF = new javax.swing.JButton();
jButtonG = new javax.swing.JButton();
jButtonH = new javax.swing.JButton();
jButtonI = new javax.swing.JButton();
jButtonJ = new javax.swing.JButton();
jButtonO = new javax.swing.JButton();
jButtonP = new javax.swing.JButton();
jButtonQ = new javax.swing.JButton();
jButtonR = new javax.swing.JButton();
jButtonK = new javax.swing.JButton();
jButtonS = new javax.swing.JButton();
jButtonL = new javax.swing.JButton();
jButtonT = new javax.swing.JButton();
jButtonN = new javax.swing.JButton();
jButtonM = new javax.swing.JButton();
jPanel1 = new javax.swing.JPanel();
jButtonO1 = new javax.swing.JButton();
jButtonP1 = new javax.swing.JButton();
jButtonK1 = new javax.swing.JButton();
jButtonL1 = new javax.swing.JButton();
jButtonN1 = new javax.swing.JButton();
jButtonM1 = new javax.swing.JButton();
jLabel2 = new javax.swing.JLabel();
jLabelAtemp = new javax.swing.JLabel();
jLabelGuess = new javax.swing.JLabel();
javax.swing.GroupLayout jFrame1Layout = new javax.swing.GroupLayout(jFrame1.getContentPane());
jFrame1.getContentPane().setLayout(jFrame1Layout);
jFrame1Layout.setHorizontalGroup(
jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
jFrame1Layout.setVerticalGroup(
jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setFont(new java.awt.Font("Tahoma", 0, 24)); // NOI18N
jLabel1.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
jLabel1.setText("Welcome to Hangman");
jButtonStart.setText("Start");
jButtonStart.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonStartActionPerformed(evt);
}
});
jButtonA.setText("A");
jButtonB.setText("B");
jButtonC.setLabel("C");
jButtonD.setText("D");
jButtonD.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonDActionPerformed(evt);
}
});
jButtonE.setText("E");
jButtonF.setText("F");
jButtonG.setText("G");
jButtonH.setText("H");
jButtonH.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonHActionPerformed(evt);
}
});
jButtonI.setText("I");
jButtonJ.setText("J");
jButtonJ.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonJActionPerformed(evt);
}
});
jButtonO.setText("O");
jButtonO.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonOActionPerformed(evt);
}
});
jButtonP.setText("P");
jButtonQ.setText("Q");
jButtonR.setText("R");
jButtonK.setText("K");
jButtonK.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonKActionPerformed(evt);
}
});
jButtonS.setText("S");
jButtonS.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonSActionPerformed(evt);
}
});
jButtonL.setText("L");
jButtonT.setText("T");
jButtonN.setText("N");
jButtonN.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonNActionPerformed(evt);
}
});
jButtonM.setText("M");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 256, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
jButtonO1.setText("O");
jButtonO1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonO1ActionPerformed(evt);
}
});
jButtonP1.setText("P");
jButtonK1.setText("K");
jButtonK1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonK1ActionPerformed(evt);
}
});
jButtonL1.setText("L");
jButtonN1.setText("N");
jButtonN1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonN1ActionPerformed(evt);
}
});
jButtonM1.setText("M");
jLabel2.setText("Atemps left:");
jLabelAtemp.setText("jLabel3");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addComponent(jButtonN1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonO1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonP1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(189, 189, 189))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(57, 57, 57)
.addComponent(jButtonK1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonL1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonM1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(jButtonA, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonB, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonC, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonD, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jButtonK, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonL, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonM, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButtonN, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonO, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonP, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonQ, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonR, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonS, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonT, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(163, 163, 163)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabelGuess, javax.swing.GroupLayout.PREFERRED_SIZE, 287, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createSequentialGroup()
.addComponent(jButtonE, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonF, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonG, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonH, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonI, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButtonJ, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(18, 18, 18)))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(192, 192, 192)
.addComponent(jLabel1))
.addGroup(layout.createSequentialGroup()
.addGap(20, 20, 20)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel2)
.addComponent(jButtonStart))
.addGap(18, 18, 18)
.addComponent(jLabelAtemp)))
.addGap(155, 155, 155)))
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addComponent(jLabel1)
.addGap(35, 35, 35)
.addComponent(jLabelGuess, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 37, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButtonA)
.addComponent(jButtonB)
.addComponent(jButtonC)
.addComponent(jButtonD)
.addComponent(jButtonE)
.addComponent(jButtonF)
.addComponent(jButtonG)
.addComponent(jButtonH)
.addComponent(jButtonI)
.addComponent(jButtonJ))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButtonK)
.addComponent(jButtonL)
.addComponent(jButtonM)
.addComponent(jButtonO)
.addComponent(jButtonP)
.addComponent(jButtonQ)
.addComponent(jButtonR)
.addComponent(jButtonS)
.addComponent(jButtonT)
.addComponent(jButtonN))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButtonK1)
.addComponent(jButtonL1)
.addComponent(jButtonM1)
.addComponent(jButtonO1)
.addComponent(jButtonP1)
.addComponent(jButtonN1))
.addGap(28, 28, 28)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jLabelAtemp))
.addGap(29, 29, 29)
.addComponent(jButtonStart)))
.addGap(19, 19, 19))
);
pack();
}// </editor-fold>
private void jButtonDActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonHActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonJActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonOActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonSActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jButtonNActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jButtonKActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonO1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jButtonK1ActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonN1ActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButtonStartActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
jLabelGuess.setText(hangman.resultstring);
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(GUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(GUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(GUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(GUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
//Hangman hangman = new Hangman();
//GUI gui = new GUI();
//gui.setVisible(true);
/* Create and display the form */
/*java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new GUI().setVisible(true);
}
});*/
}
// Variables declaration - do not modify
private javax.swing.JButton jButtonA;
private javax.swing.JButton jButtonB;
private javax.swing.JButton jButtonC;
private javax.swing.JButton jButtonD;
private javax.swing.JButton jButtonE;
private javax.swing.JButton jButtonF;
private javax.swing.JButton jButtonG;
private javax.swing.JButton jButtonH;
private javax.swing.JButton jButtonI;
private javax.swing.JButton jButtonJ;
private javax.swing.JButton jButtonK;
private javax.swing.JButton jButtonK1;
private javax.swing.JButton jButtonL;
private javax.swing.JButton jButtonL1;
private javax.swing.JButton jButtonM;
private javax.swing.JButton jButtonM1;
private javax.swing.JButton jButtonN;
private javax.swing.JButton jButtonN1;
private javax.swing.JButton jButtonO;
private javax.swing.JButton jButtonO1;
private javax.swing.JButton jButtonP;
private javax.swing.JButton jButtonP1;
private javax.swing.JButton jButtonQ;
private javax.swing.JButton jButtonR;
private javax.swing.JButton jButtonS;
private javax.swing.JButton jButtonStart;
private javax.swing.JButton jButtonT;
private javax.swing.JFrame jFrame1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabelAtemp;
private javax.swing.JLabel jLabelGuess;
private javax.swing.JPanel jPanel1;
// End of variables declaration
}
The message error when I run the application.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at hangman.GUI.jButtonStartActionPerformed(GUI.java:400)
at hangman.GUI.access$000(GUI.java:12)
at hangman.GUI$1.actionPerformed(GUI.java:96)

It seems that in the GUI class you declare a member variable, Hangman hangman, but you never initialize it. Therefore, the code jLabelGuess.setText(hangman.resultstring); and similar calls will result in a null pointer exception.

In the GUI class, you just only declare Hangman hangman, which mean the class Hangman has never been called to execute or initialized any value. Therefore, hangman.resultstring is null when you called jLabelGuess.setText(hangman.resultstring), since resultstring value is get from Hangman class; and cause Null Pointer Exception error at jLabelGuess.setText() and the function jButtonStartActionPerformed()
You might fix it if you initialize the Hangman class: Hangman hangman = new Hangman(); Or calling the function that initializes the value of resultstring which is hangman.initialComponent()

Cant add dynamically created checkbox to jPanel

I want to add checkboxes to a jpanel, which is on a jFrame. The UI was made on netbeans and i have copied the code to work on its functionality on eclipse.
I cant get my checkboxes come over the Jpanel.
The code
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JCheckBox;
import javax.swing.border.Border;
public class QueryBuilderUI extends javax.swing.JFrame {
QueryBuilderMethods objQBM = new QueryBuilderMethods();
DefaultComboBoxModel<String> repoModel = new DefaultComboBoxModel<String>();
public QueryBuilderUI() {
getRepositoryListing();
initComponents();
}
private void getRepositoryListing()
{
repoModel = new QueryBuilderMethods().getAllRepositoryName();
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jComboBox1 = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
jComboBox2 = new javax.swing.JComboBox();
jLabel3 = new javax.swing.JLabel();
jPanel1 = new javax.swing.JPanel();
jTextField1 = new javax.swing.JTextField();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Choose Repository");
jComboBox1.setModel(repoModel);
jComboBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox1ItemStateChanged(evt);
}
});
jLabel2.setText("Choose Table");
//jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
jComboBox2.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox2ItemStateChanged(evt);
}
});
jLabel3.setText("Choose Columns");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
Border border = BorderFactory.createTitledBorder("Select Columns");
jPanel1.setBorder(border);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 459, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 124, Short.MAX_VALUE)
);
jTextField1.setText("jTextField1");
jLabel4.setText("Generated Query");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGap(57, 57, 57)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addComponent(jLabel3)
.addComponent(jLabel4)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 412, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(65, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(44, 44, 44)
.addComponent(jLabel4)
.addGap(18, 18, 18)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(92, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if(evt.getStateChange()== ItemEvent.SELECTED){
Object item = evt.getItem();
DefaultComboBoxModel<String> modelTable = objQBM.getAllTablesForRepo(item.toString());
jComboBox2.setModel(modelTable);
}
}
private void jComboBox2ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if(evt.getStateChange()== ItemEvent.SELECTED){
Object item = evt.getItem();
String RepoName = jComboBox1.getSelectedItem().toString();
List<String> columnNames = objQBM.getAllColumnsForTable(item.toString());
addCheckBox(columnNames);
}
}
private void addCheckBox(List<String> columnNames)
{
int numberCheckBox = columnNames.size();
JCheckBox[] checkBoxList = new JCheckBox[numberCheckBox];
for(int i = 0; i < numberCheckBox; i++) {
checkBoxList[i] = new JCheckBox("hi"+i);
jPanel1.add(checkBoxList[i]);
}
jPanel1.revalidate();
}
public static void main(String args[]) {
// java.awt.EventQueue.invokeLater(new Runnable() {
// public void run() {
new QueryBuilderUI().setVisible(true);
// }
// });
}
// Variables declaration - do not modify
private javax.swing.JComboBox jComboBox1;
private javax.swing.JComboBox jComboBox2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField jTextField1;
// End of variables declaration
}
the UI Looks like this
The checkboxes needs to be created dynamically according to what is selected on jComboBox2.

Your jPanel1 JPanel is being constrained by its layout, GroupLayout, which does not take kindly to the addition of new components without significant additions to code that are difficult to make, since GroupLayout was not built to be used for hand coding but rather for GUI-builder coding. I suggest that you build your GUI with much more coder-friendly layouts, or better still, combinations of nested JPanels each using a simpler layout, ones that are much more conducive to the addition of new components, and then your problems will be more easily solved.
You could even still use GroupLayout for the main of your GUI if you desire, but just not for jPanel1. I suggest that you consider using GridLayout or GridBagLayout to add a grid of JCheckBoxes. Or even FlowLayout. For example the following code uses the default JPanel's FlowLayout:
import java.awt.Dimension;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JCheckBox;
import javax.swing.border.Border;
public class QueryBuilderUI extends javax.swing.JFrame {
protected static final int PREF_W = 400;
protected static final int PREF_H = 200;
QueryBuilderMethods objQBM = new QueryBuilderMethods();
DefaultComboBoxModel<String> repoModel = new DefaultComboBoxModel<String>();
public QueryBuilderUI() {
getRepositoryListing();
initComponents();
}
private void getRepositoryListing() {
repoModel = new QueryBuilderMethods().getAllRepositoryName();
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jComboBox1 = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
jComboBox2 = new javax.swing.JComboBox();
jLabel3 = new javax.swing.JLabel();
jPanel1 = new javax.swing.JPanel() {
#Override
// !! so the JPanel has some size. This is a shameless kludge *****
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
};
jTextField1 = new javax.swing.JTextField();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Choose Repository");
jComboBox1.setModel(repoModel);
jComboBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox1ItemStateChanged(evt);
}
});
jLabel2.setText("Choose Table");
// jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] {
// "Item 1", "Item 2", "Item 3", "Item 4" }));
jComboBox2.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox2ItemStateChanged(evt);
}
});
jLabel3.setText("Choose Columns");
// *************** Note Changes Below ****************
// !! javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(
// !! jPanel1);
// !! jPanel1.setLayout(jPanel1Layout);
// !! jPanel1 now uses JPanel's default FlowLayout
Border border = BorderFactory.createTitledBorder("Select Columns");
jPanel1.setBorder(border);
jTextField1.setText("jTextField1");
jLabel4.setText("Generated Query");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(
getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(layout
.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(
layout.createSequentialGroup()
.addContainerGap()
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(
layout.createSequentialGroup()
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(
jLabel1)
.addComponent(
jLabel2))
.addGap(57, 57, 57)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(
jComboBox1,
javax.swing.GroupLayout.PREFERRED_SIZE,
106,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(
jComboBox2,
javax.swing.GroupLayout.PREFERRED_SIZE,
106,
javax.swing.GroupLayout.PREFERRED_SIZE)))
.addComponent(jLabel3)
.addComponent(jLabel4)
.addComponent(
jPanel1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(
jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE,
412,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(65, Short.MAX_VALUE)));
layout.setVerticalGroup(layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING).addGroup(
layout.createSequentialGroup()
.addGap(18, 18, 18)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jComboBox1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jComboBox2,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addComponent(jLabel3)
.addPreferredGap(
javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(44, 44, 44)
.addComponent(jLabel4)
.addGap(18, 18, 18)
.addComponent(jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(92, Short.MAX_VALUE)));
pack();
}// </editor-fold>
private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if (evt.getStateChange() == ItemEvent.SELECTED) {
Object item = evt.getItem();
DefaultComboBoxModel<String> modelTable = objQBM
.getAllTablesForRepo(item.toString());
jComboBox2.setModel(modelTable);
}
}
private void jComboBox2ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if (evt.getStateChange() == ItemEvent.SELECTED) {
Object item = evt.getItem();
String RepoName = jComboBox1.getSelectedItem().toString();
List<String> columnNames = objQBM.getAllColumnsForTable(item
.toString());
addCheckBox(columnNames);
}
}
private void addCheckBox(List<String> columnNames) {
int numberCheckBox = columnNames.size();
JCheckBox[] checkBoxList = new JCheckBox[numberCheckBox];
System.out.println("numberCheckBox = " + numberCheckBox);
for (int i = 0; i < numberCheckBox; i++) {
checkBoxList[i] = new JCheckBox("hi" + i);
jPanel1.add(checkBoxList[i]);
}
jPanel1.revalidate();
jPanel1.repaint();
System.out.println("check boxes added");
}
public static void main(String args[]) {
// java.awt.EventQueue.invokeLater(new Runnable() {
// public void run() {
new QueryBuilderUI().setVisible(true);
// }
// });
}
// Variables declaration - do not modify
private javax.swing.JComboBox jComboBox1;
private javax.swing.JComboBox jComboBox2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField jTextField1;
// End of variables declaration
}
// mock code added so that the above code will compile and run
// because you didn't give us this code
class QueryBuilderMethods {
public DefaultComboBoxModel<String> getAllRepositoryName() {
DefaultComboBoxModel<String> cModel = new DefaultComboBoxModel<>();
for (String item : new String[] { "one", "two", "three", "four", "five" }) {
cModel.addElement(item);
}
return cModel;
}
public List<String> getAllColumnsForTable(String string) {
List<String> columns = new ArrayList<>();
for (String item : new String[] { "col 1", "col 2", "col 3", "col 4" }) {
columns.add(item);
}
return columns;
}
public DefaultComboBoxModel<String> getAllTablesForRepo(String string) {
DefaultComboBoxModel<String> cModel = new DefaultComboBoxModel<>();
for (String item : new String[] { "repo one", "repo two", "repo three",
"repo four", "repo five" }) {
cModel.addElement(item);
}
return cModel;
}
}

Netbeans: string not displaying

I want to display string in textbox of vpsfame class below my code, but I am unable to dispaly it. Can you give me suggestion this string in new8 class show in code and serial class gives me string from gps continue. It also displays it at run time via System.out.println, but does not display it through the textbox of vpsfame class
package vpspro;
import javax.comm.*;
import java.util.*;
import java.io.*;
public class Serial
{
public void com() throws UnsupportedCommOperationException, IOException, TooManyListenersException
{
int c=1;
String wantedPortName="COM6";
Enumeration portIdentifiers = CommPortIdentifier.getPortIdentifiers();
CommPortIdentifier portId = null;
while(portIdentifiers.hasMoreElements())
{
CommPortIdentifier pid = (CommPortIdentifier) portIdentifiers.nextElement();
if(pid.getPortType() == CommPortIdentifier.PORT_SERIAL &&
pid.getName().equals(wantedPortName))
{
portId = pid;
break;
}
}
if(portId == null)
{
System.err.println("Could not find serial port " + wantedPortName);
System.exit(1);
}
else
{
System.out.println("system find gps reciever");
}
SerialPort port = null;
try {
port = (SerialPort) portId.open(
"RMC",
1);
System.out.println("all are ok");
} catch(PortInUseException e) {
System.err.println("Port already in use: " + e);
System.exit(1);
}
port.setSerialPortParams(
4800,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
BufferedReader is = null;
try {
is = new BufferedReader(new InputStreamReader(port.getInputStream()));
System.out.println("data is ok");
} catch (IOException e) {
System.err.println("Can't open input stream: write-only");
is = null;
}
String pt=null;
while(true)
{
String st = is.readLine();
System.out.print("(" + c + ")");
c++;
new8 obj1 = new new8();
obj1.decode(st);
System.out.println(st);
st = st.replace(st, "");
}
if (is != null) is.close();
/*if (os != null) os.close();*/
if (port != null) port.close();
}
}
this code for start communication with serial class
package vpspro;
import java.io.IOException;
import java.util.TooManyListenersException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.comm.UnsupportedCommOperationException;
public class getcon extends javax.swing.JFrame {
public getcon() {
initComponents();
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
sc = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
br = new javax.swing.JComboBox();
help = new javax.swing.JButton();
ok = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("select comport");
sc.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "COM10", "COM11", "COM12" }));
sc.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
scActionPerformed(evt);
}
});
sc.addInputMethodListener(new java.awt.event.InputMethodListener() {
public void caretPositionChanged(java.awt.event.InputMethodEvent evt) {
}
public void inputMethodTextChanged(java.awt.event.InputMethodEvent evt) {
scInputMethodTextChanged(evt);
}
});
jLabel2.setText("select buad rate");
br.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "4800", "1900", "150000" }));
br.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
brActionPerformed(evt);
}
});
help.setText("help");
ok.setText("ok");
ok.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
okActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addGap(67, 67, 67)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(sc, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(105, 105, 105))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(171, Short.MAX_VALUE)
.addComponent(ok)
.addGap(28, 28, 28)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel2)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(help)
.addComponent(br, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(80, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(57, 57, 57)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(sc, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(br, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(57, 57, 57)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(help)
.addComponent(ok))
.addContainerGap(118, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void brActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if(evt.getSource()==br)
br.addItem("4800");
br.addItem("9600");
}
private void scActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if(evt.getSource()==sc)
sc.addItem("COM6");
sc.addItem("COM7");
}
private void scInputMethodTextChanged(java.awt.event.InputMethodEvent evt) {
// TODO add your handling code here:
if(evt.getSource()==sc)
sc.addItem("COM6");
sc.addItem("COM7");
}
private void okActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if(evt.getSource()==ok)
{
try {
new Serial().com();
} catch (UnsupportedCommOperationException ex) {
Logger.getLogger(getcon.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(getcon.class.getName()).log(Level.SEVERE, null, ex);
} catch (TooManyListenersException ex) {
Logger.getLogger(getcon.class.getName()).log(Level.SEVERE, null, ex);
}
new new8();
}
}
public void getcom() {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new getcon().setVisible(true);
}
});
}
private javax.swing.JComboBox br;
private javax.swing.JButton help;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
public javax.swing.JButton ok;
private javax.swing.JComboBox sc;
}
this code decoding my gps string and dispaly and hear problem created i can not dispaly below string in textbox when i rum program textbox are empty.
package vpa.io.*;
import vpspro.vpsfame;
public class new8
{
static String[] a2;
static String a1[];
static String c;
public static String[] t;
public void decode(String st)
{
if(st.isEmpty())
{
System.out.println("System has proble");
vpsfame obj=new vpsfame();
obj.ab.setText("ok");
}
else
{
a1=st.split("\\$",0);
a2=a1[1].split("\\*",0);
checksum();
if(a2[1].equalsIgnoreCase(c))
{
t=st.split(",",0);
switch (t[0].charAt(0))
{
case '$':
String s=t[0].substring(3,6);
String s3="RMC";
if (s.compareTo(s3)==0)
{
System.out.println(" NMEA 0183 Details.....");
System.out.println("System identity: "+t[0].substring(1,3));
System.out.println("NMEA Formate: "+t[0].substring(3,6));
System.out.println("(UTC)Time: "+t[1].substring(1,2));
new vpsfame().ac.setText(t[1].substring(1,2));
System.out.println("Lattitude: "+t[3]);
System.out.println("Direction of Lattitude: "+t[4]);
new vpsfame().ab.setText(t[3].concat(t[4]));
System.out.println("Longitude: "+t[5]);
System.out.println("Direction of Longitude: "+t[6]);
new vpsfame().bc.setText(t[5].concat(t[6]));
System.out.println("Speed over Ground: "+t[7]);
new vpsfame().cd.setText(t[7]);
/*System.out.println("Track mode: "+t[8]);
System.out.println(st.isEmpty());
System.out.println("DATE: "+t[9]);
System.out.println("adjustment declination "+t[10]);
System.out.println("Direction of Magnetic variation: "+t[11].charAt(0));*/
}
}
else
System.out.println(" Invalid Formate...");
break;
default:
System.out.println(" Invalid DATA....");
}
}
else
System.out.println(" no match checksum");
}
}
public static void checksum()
{
int l=a2[0].length();
char[] a=a2[0].toCharArray();
int b=0;
for(int i=0;i<l;i++)
{
b=b^a[i];
}
c=Integer.toHexString(b);
}
}
and this is my main class
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/*
* vpsfame.java
*
* Created on Jan 26, 2013, 11:02:32 PM
*/
package vpspro;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Font;
import java.awt.Image;
import java.awt.TextField;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.TooManyListenersException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.comm.UnsupportedCommOperationException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JComboBox;
import javax.swing.JFrame;
/**
*
* #author DHARMA
*/
public class vpsfame extends javax.swing.JFrame {
public vpsfame()
{
initComponents();
}
/** Creates new form vpsfame */
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jComboBox1 = new javax.swing.JComboBox();
ab = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
bc = new javax.swing.JTextField();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
ac = new javax.swing.JTextField();
jLabel5 = new javax.swing.JLabel();
cd = new javax.swing.JTextField();
jPanel1 = new javax.swing.JPanel();
jMenuBar1 = new javax.swing.JMenuBar();
jMenu1 = new javax.swing.JMenu();
gc = new javax.swing.JMenuItem();
jMenuItem2 = new javax.swing.JMenuItem();
lm = new javax.swing.JMenuItem();
jMenuItem4 = new javax.swing.JMenuItem();
jMenuItem5 = new javax.swing.JMenuItem();
jMenuItem6 = new javax.swing.JMenuItem();
jMenu2 = new javax.swing.JMenu();
jMenuItem7 = new javax.swing.JMenuItem();
jMenuItem8 = new javax.swing.JMenuItem();
jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
ab.setEditable(false);
ab.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
abActionPerformed(evt);
}
});
jLabel1.setText("latitude");
jLabel2.setText("longitude");
bc.setText(" ");
bc.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
bcActionPerformed(evt);
}
});
jLabel4.setText("UTC");
ac.setText(" ");
ac.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
acActionPerformed(evt);
}
});
jLabel5.setText("Speed of vessel");
cd.setText(" ");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 621, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 368, Short.MAX_VALUE)
);
jMenu1.setText("File");
gc.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_G, java.awt.event.InputEvent.CTRL_MASK));
gc.setIcon(new javax.swing.ImageIcon("C:\\Users\\DHARMA\\Desktop\\png\\20x20\\55.png")); // NOI18N
gc.setText("get connection");
gc.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
gcActionPerformed(evt);
}
});
jMenu1.add(gc);
jMenuItem2.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_T, java.awt.event.InputEvent.CTRL_MASK));
jMenuItem2.setText("track");
jMenu1.add(jMenuItem2);
lm.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_M, java.awt.event.InputEvent.ALT_MASK));
lm.setText("load map");
lm.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
lmActionPerformed(evt);
}
});
jMenu1.add(lm);
jMenuItem4.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_S, java.awt.event.InputEvent.CTRL_MASK));
jMenuItem4.setText("data save");
jMenu1.add(jMenuItem4);
jMenuItem5.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_T, java.awt.event.InputEvent.META_MASK));
jMenuItem5.setText("set time zone");
jMenu1.add(jMenuItem5);
jMenuItem6.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_Q, java.awt.event.InputEvent.CTRL_MASK));
jMenuItem6.setText("quit");
jMenu1.add(jMenuItem6);
jMenuBar1.add(jMenu1);
jMenu2.setText("view");
jMenuItem7.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_S, java.awt.event.InputEvent.ALT_MASK));
jMenuItem7.setText("saved data");
jMenu2.add(jMenuItem7);
jMenuItem8.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_A, java.awt.event.InputEvent.ALT_MASK));
jMenuItem8.setText("about us");
jMenu2.add(jMenuItem8);
jMenuBar1.add(jMenu2);
setJMenuBar(jMenuBar1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(52, 52, 52)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel5)
.addGap(19, 19, 19))
.addGroup(layout.createSequentialGroup()
.addComponent(cd, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(35, 35, 35))
.addComponent(ab, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 95, Short.MAX_VALUE)
.addComponent(jLabel3)
.addComponent(ac, javax.swing.GroupLayout.DEFAULT_SIZE, 95, Short.MAX_VALUE)
.addComponent(jLabel4)
.addComponent(bc, javax.swing.GroupLayout.DEFAULT_SIZE, 95, Short.MAX_VALUE)
.addComponent(jLabel2)
.addComponent(jLabel1))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGap(11, 11, 11)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addGap(25, 25, 25)
.addComponent(jLabel1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(ab, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(43, 43, 43)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jLabel2)
.addGap(16, 16, 16)
.addComponent(bc, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 56, Short.MAX_VALUE)
.addComponent(jLabel4)
.addGap(18, 18, 18)
.addComponent(ac, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(45, 45, 45)
.addComponent(jLabel5)
.addGap(18, 18, 18)
.addComponent(cd, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap())
);
pack();
}// </editor-fold>
private void gcActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if(evt.getSource()==gc)
{
getcon obj3=new getcon();
obj3.setVisible(true);
}
}
private void lmActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void abActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void acActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void bcActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) throws UnsupportedCommOperationException, IOException, TooManyListenersException {
/*public vpsfame()
{
initComponents();*/
new new8();
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
/*URL url=getClass().getResource("C:\\Users\\DHARMA\\Documents\\NetBeansProjects\\vpspro\\src");*/
vpsfame obj4=new vpsfame();
new vpsfame().setBackground(Color.yellow);
obj4.setSize(1000,
500);
ImageIcon image1=new ImageIcon("C:\\Users\\DHARMA\\Documents\\NetBeansProjects\\vpspro\\src");
System.out.println("jjdfhj");
obj4.setIconImage(image1.getImage());
obj4.setTitle("VPS");
obj4.setVisible(true);
new new8();
}
});
}
/*public vpsfame()
{
fm=new JFrame("VPS");
fm.setSize(1000, 1000);
fm.setVisible(true);
fm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}*/
// Variables declaration - do not modify
public static javax.swing.JTextField ab;
public javax.swing.JTextField ac;
public static javax.swing.JTextField bc;
public javax.swing.JTextField cd;
private javax.swing.JMenuItem gc;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem2;
private javax.swing.JMenuItem jMenuItem4;
private javax.swing.JMenuItem jMenuItem5;
private javax.swing.JMenuItem jMenuItem6;
private javax.swing.JMenuItem jMenuItem7;
private javax.swing.JMenuItem jMenuItem8;
private javax.swing.JPanel jPanel1;
private javax.swing.JMenuItem lm;
// End of variables declaration
}

I would seriously advise you to take a time out, and refactor all of your code. Igonoring that in the class new8, in method decode replace this code:
new vpsfame().ac.setText(t[1].substring(1,2));
System.out.println("Lattitude: "+t[3]);
System.out.println("Direction of Lattitude: "+t[4]);
new vpsfame().ab.setText(t[3].concat(t[4]));
System.out.println("Longitude: "+t[5]);
System.out.println("Direction of Longitude: "+t[6]);
new vpsfame().bc.setText(t[5].concat(t[6]));
System.out.println("Speed over Ground: "+t[7]);
new vpsfame().cd.setText(t[7]);
With this:
//use one object, dont just create new frames
vpsfame myFrame = new vpsfame();
myFrame.ac.setText(t[1].substring(1,2));
System.out.println("Lattitude: "+t[3]);
System.out.println("Direction of Lattitude: "+t[4]);
myFrame.ab.setText(t[3].concat(t[4]));
System.out.println("Longitude: "+t[5]);
System.out.println("Direction of Longitude: "+t[6]);
myFrame.bc.setText(t[5].concat(t[6]));
System.out.println("Speed over Ground: "+t[7]);
myFrame.cd.setText(t[7]);
//Also set the frame to visible, so it can be displayed once you've done all this work.
myFrame.setVisible(true);
The problem is that:
Firstly, you are creating multiple vpsframe objects where you should only have one. It makes no sense to create 5 frames where each will have 4 empty fields. Create one object and initialise all it's fields rather than using 5 diffrent objects.
You are not tracking the objects you are creating, the garbage collector will just get rid of the, so create one object, assign it to a variable and use that.
Set the vpsfame object to visible, otherwise you will never see it.
Your code also needs refactoring, you should be using the camelCase naming convention, and classes should always begin with Capital letters.

NetBeans Java Project Won't Display GUI Window Despite No Error

I am trying to build a java project using Netbeans IDE 7.1.
I somehow can't see or view the GUI window that I have created.
Please kindly advise.
In my class:
package rmiSimpleCalc;
public class RMISimpleCalculatorMain {
public static void main(String[] args) {
MainCalculator calc = new MainCalculator();
calc.setVisible(true);
}
}
the MainCalculator is the GUI window I would like to run. It somehow wont't display.
There is NO error message in my console tough..
Here is the MainCalculator code:
package rmiSimpleCalc;
import java.rmi.*;
public class MainCalculator extends javax.swing.JPanel {
public MainCalculator() {
initComponents();
ComboBoxOperator.addItem("+");
ComboBoxOperator.addItem("-");
ComboBoxOperator.addItem("/");
ComboBoxOperator.addItem("*");
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
txtFirstDigit = new javax.swing.JTextField();
txtSecondDigit = new javax.swing.JTextField();
btnCalculate = new javax.swing.JButton();
lblFirstDigit = new javax.swing.JLabel();
lblSecondDigit = new javax.swing.JLabel();
ComboBoxOperator = new javax.swing.JComboBox();
lblOperator = new javax.swing.JLabel();
lblResult = new javax.swing.JLabel();
lblHeader = new javax.swing.JLabel();
btnConfigureServer = new javax.swing.JButton();
txtResult = new javax.swing.JTextField();
btnCalculate.setText("Calculate");
btnCalculate.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnCalculateActionPerformed(evt);
}
});
lblFirstDigit.setText("First Digit");
lblSecondDigit.setText("Second Digit");
ComboBoxOperator.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
lblOperator.setText("Operator");
lblResult.setText("Result");
lblHeader.setText("RMI Simple Calculator");
btnConfigureServer.setText("Configure Server");
btnConfigureServer.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnConfigureServerActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(lblFirstDigit, javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(lblSecondDigit, javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(lblOperator, javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(lblResult, javax.swing.GroupLayout.Alignment.TRAILING))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(lblHeader)
.addGroup(layout.createSequentialGroup()
.addComponent(ComboBoxOperator, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(btnCalculate))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(txtSecondDigit)
.addComponent(txtFirstDigit, javax.swing.GroupLayout.PREFERRED_SIZE, 128, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(txtResult, javax.swing.GroupLayout.PREFERRED_SIZE, 125, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnConfigureServer)))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(12, 12, 12)
.addComponent(lblHeader)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(txtFirstDigit, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(lblFirstDigit))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(txtSecondDigit, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(lblSecondDigit))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(ComboBoxOperator, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(lblOperator)
.addComponent(btnCalculate))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(lblResult)
.addComponent(txtResult, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(btnConfigureServer)
.addContainerGap(24, Short.MAX_VALUE))
);
}
private void btnConfigureServerActionPerformed(java.awt.event.ActionEvent evt) {
}
private void btnCalculateActionPerformed(java.awt.event.ActionEvent evt) {
double firstdigit;
double seconddigit;
String operator;
firstdigit = Double.valueOf(txtFirstDigit.getText());
seconddigit = Double.valueOf(txtSecondDigit.getText());
operator = ComboBoxOperator.getSelectedItem().toString();
try
{
CoreInterface coreobj = (CoreInterface) Naming.lookup("localhost/Core");
double result = (coreobj.calc(firstdigit,seconddigit,operator));
txtResult.setText(Double.toString(result));
}
catch(Exception e)
{
txtResult.setText("e");
}
}
private javax.swing.JComboBox ComboBoxOperator;
private javax.swing.JButton btnCalculate;
private javax.swing.JButton btnConfigureServer;
private javax.swing.JLabel lblFirstDigit;
private javax.swing.JLabel lblHeader;
private javax.swing.JLabel lblOperator;
private javax.swing.JLabel lblResult;
private javax.swing.JLabel lblSecondDigit;
private javax.swing.JTextField txtFirstDigit;
private javax.swing.JTextField txtResult;
private javax.swing.JTextField txtSecondDigit;
// End of variables declaration
}
Any advise is appreciated.

The MainCalculator class is a JPanel. A JPanel can't just be displayed like that, it has to be part of a Window. Add it to a JFrame and call setVisible(true) on the JFrame.
Also, #npinti's advice is very good: execute GUI-related code in the EDT thread.

The issue is most likely in this section:
public static void main(String[] args) {
MainCalculator calc = new MainCalculator();
calc.setVisible(true);
}
You need to make any GUI related tasks within the Event Dispatcher Thread (EDT).
Try something like so:
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
MainCalculator calc = new MainCalculator();
calc.setVisible(true);
}
});
}

populating a jcombobox with database information

I know I am missing something simple, I think in getting the combobox to access the array.
package my.freelancebillingapp;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.ArrayList;
import javax.swing.*;
public class billingInfoUI extends javax.swing.JFrame {
public billingInfoUI() {
initComponents();
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
hoursWorked = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
flatRate = new javax.swing.JTextField();
jScrollPane1 = new javax.swing.JScrollPane();
workType = new javax.swing.JList();
jScrollPane2 = new javax.swing.JScrollPane();
jList2 = new javax.swing.JList();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jComboBox1 = new javax.swing.JComboBox();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Billing Information", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.ABOVE_BOTTOM, new java.awt.Font("Bleeding Cowboys", 0, 48))); // NOI18N
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 457, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
hoursWorked.setHorizontalAlignment(javax.swing.JTextField.CENTER);
hoursWorked.setText("Hours Worked");
hoursWorked.setBorder(null);
jLabel1.setText("Or");
flatRate.setHorizontalAlignment(javax.swing.JTextField.CENTER);
flatRate.setText("Flat Rate");
flatRate.setBorder(null);
workType.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Work Type", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.TOP));
workType.setModel(new javax.swing.AbstractListModel() {
String[] strings = { "Web Design", "Graphic Design", "Consulting" };
public int getSize() { return strings.length; }
public Object getElementAt(int i) { return strings[i]; }
});
workType.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
jScrollPane1.setViewportView(workType);
jList2.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Any Extras?", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.TOP));
jList2.setModel(new javax.swing.AbstractListModel() {
String[] strings = { "Blog", "Forum", "Templating", "Rush Delivery" };
public int getSize() { return strings.length; }
public Object getElementAt(int i) { return strings[i]; }
});
jScrollPane2.setViewportView(jList2);
jButton1.setText("Save");
jButton1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jButton1MouseClicked(evt);
}
});
jButton2.setText("Invoice");
jButton3.setText("Close");
jButton3.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jButton3MouseClicked(evt);
}
});
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
jComboBox1.setModel(customers);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(89, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(hoursWorked, javax.swing.GroupLayout.PREFERRED_SIZE, 83, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(48, 48, 48)
.addComponent(jLabel1)
.addGap(1, 1, 1))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 142, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(31, 31, 31)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(49, 49, 49)
.addComponent(flatRate, javax.swing.GroupLayout.PREFERRED_SIZE, 56, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(79, 79, 79))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(62, 62, 62)
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 103, Short.MAX_VALUE)
.addComponent(jButton2)
.addGap(79, 79, 79)
.addComponent(jButton3)
.addGap(52, 52, 52))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(134, Short.MAX_VALUE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 238, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(107, 107, 107))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(30, 30, 30)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(hoursWorked, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(flatRate, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1))
.addGap(20, 20, 20)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 86, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 40, Short.MAX_VALUE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(51, 51, 51)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton2)
.addComponent(jButton3)
.addComponent(jButton1))
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButton3MouseClicked(java.awt.event.MouseEvent evt) {
new FreelanceBillingUI().setVisible(true);
setVisible(false);
}
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {
String hoursWorkedtxt = hoursWorked.getText();
String flatRatetxt = flatRate.getText();
workType.getSelectedValue();
workType.toString();
Object workTypetxt = workType.getSelectedValue();
if(hoursWorkedtxt.contains("H")){
hoursWorkedtxt = "0";
}else{
flatRatetxt = "0";
}
}
public class CustomerData {
private static final String JDBC_CONNECTION_URL = "jdbc:mysql://localhost/test";
private static final String DATABASE_USER = "root";
private static final String DATABASE_PASSWORD = "root";
private static final String SQL_FETCH_CUSTOMERS = "SELECT custName FROM customers";
private Connection connection = null;
public CustomerData(){
initConnection();
}
private void initConnection() {
try {
//load the mysql driver
Class.forName("com.mysql.jdbc.Driver");
//create the database connection
connection = DriverManager.getConnection(JDBC_CONNECTION_URL, DATABASE_USER, DATABASE_PASSWORD);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
public void closeConnection(){
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
connection = null;
}
}
}
public ArrayList fetchCustomerData(){
if (connection != null){
Statement statement = null;
try {
statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(SQL_FETCH_CUSTOMERS);
return convertResultSetToCustomersArray(resultSet);
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (statement != null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}else{
System.out.println("NO VALID DATABASE CONNECTION, CAN'T FETCH CUSTOMER DATA!");
}
return new ArrayList();
}
private ArrayList convertResultSetToCustomersArray(ResultSet results) throws SQLException{
ArrayList customers = new ArrayList();
while (results.next()){
customers.add(results.getString("custName"));
}
return customers;
}
}
private void initData(){
CustomerData customerData = new CustomerData();
ArrayList custArrayList = customerData.fetchCustomerData();
customers = (String[]) custArrayList.toArray(new String[0]);
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new billingInfoUI().setVisible(true);
}
});
}
private String[] customers = null;
private javax.swing.JTextField flatRate;
private javax.swing.JTextField hoursWorked;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JList jList2;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JList workType;
}

There is too much code there to look at 90% of it is NOT related to adding data in a combo box. You have a dozen other components which clutter the code so we can't see what actually happening with the comobo box.
It you really need help then post a SSCCE.
That is, create a simple frame and load hard coded data into the combo box.
Then create a simple program to read data from the database and use System.out.println(...) to display each value.
Once you've mastered the two basic steps, then put the two programs together to load a combobox dynamically from a database.
Finally add the rest of you components to the frame.
Break you problem down into small, manageable steps and you will be able to debug it easier.

A few points:
Wading through your code, I don't see a call to initData being made anywhere. Without that call, you wont call your database code. Without the database call, you wont get the data.
JComboBox does not have a setModel method that takes an array. You can wrap your array in a DefaultComboBoxModel and set that on the model.
It is good to keep in mind that blocking calls like database access should not be made in the AWT painting thread, and neither should calls that update the GUI be made outside of the AWT thread. You should look into creating your GUI and grabbing your data in separate threads, and making use of SwingUtlities.invokeLater or similar tools to update your GUI.