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Show next question when next button is clicked

I trying to read file in java. When click next button, how can I show second question when next button is clicked?
My .txt file content is like this
1. What is his name
A.John
B.David
2. How old is him?
A.24
B.27
So far I am able to display the first question in JTextField.
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.io.File;
import java.io.FileReader;
public class NewJFrame extends javax.swing.JFrame {
/**
* Creates new form NewJFrame
*/
public NewJFrame() throws IOException {
initComponents();
setLocationRelativeTo(null);
pack();
File file = new File("/home/xxx/Desktop/englishQuestion.txt");
StringBuilder sb = new StringBuilder();
try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
String line;
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
if (line.equals("")) {
break;
}
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
String result = sb.toString();
jTextArea1.setText(result);
}
/**
* 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() {
jButton1 = new javax.swing.JButton();
textField1 = new java.awt.TextField();
label1 = new java.awt.Label();
jScrollPane1 = new javax.swing.JScrollPane();
jTextArea1 = new javax.swing.JTextArea();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("Next");
textField1.setName("\"\""); // NOI18N
textField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
textField1ActionPerformed(evt);
}
});
label1.setText("Answer:");
jTextArea1.setColumns(20);
jTextArea1.setRows(5);
jScrollPane1.setViewportView(jTextArea1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(0, 0, Short.MAX_VALUE)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(textField1, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 57, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(28, 28, 28))
.addGroup(layout.createSequentialGroup()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 421, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 206, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(textField1, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton1))
.addContainerGap())
);
label1.getAccessibleContext().setAccessibleName("Answer: ");
pack();
}// </editor-fold>
private void textField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
/**
* #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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new NewJFrame().setVisible(true);
} catch (IOException ex) {
Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
private java.awt.Label label1;
private java.awt.TextField textField1;
// End of variables declaration
}

I refactored the file lines to be like this:
q1 = What is his name? | John | David
q2 = How old is him? | 24 | 27
This way, each question information is in a single line and is easier to parse. You just have to load it as a property file and the q1 and q2 would be the keys, and what is after = would be the values. After that, split it by | or whatever you decide to use.
I refactored your code to look like this:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
public class NewJFrame extends javax.swing.JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
private Properties props = new Properties();
private List<Question> questionList = new ArrayList<>();
private int currentQuestionIndex = -1;
private class Question {
private String question;
private String answer1;
private String answer2;
#Override
public String toString() {
return "Question [question=" + question + ", answer1=" + answer1 + ", answer2=" + answer2 + "]";
}
public Question(String question, String answer1, String answer2) {
this.question = question;
this.answer1 = answer1;
this.answer2 = answer2;
}
public String getQuestion() {
return question;
}
public String getAnswer1() {
return answer1;
}
public String getAnswer2() {
return answer2;
}
}
public void showNextQuestion() {
currentQuestionIndex++;
if (currentQuestionIndex >= questionList.size()) {
jTextArea1.setText("No more questions available.");
return;
}
jTextArea1.setText("");
Question currentQuestion = questionList.get(currentQuestionIndex);
String newLine = "\n";
jTextArea1.append(currentQuestion.getQuestion() + newLine);
jTextArea1.append("A. " + currentQuestion.getAnswer1() + newLine);
jTextArea1.append("B. " + currentQuestion.getAnswer2());
}
public NewJFrame() throws IOException {
initComponents();
setLocationRelativeTo(null);
pack();
Path path = Paths.get("/home/xxx/Desktop/englishQuestion.txt");
props.load(Files.newInputStream(path));
props.forEach((key, value) -> {
String v = (String) value;
System.out.println(v);
String[] token = v.split("\\|");
String question = token[0];
String answer1 = token[1];
String answer2 = token[2];
Question q = new Question(question, answer1, answer2);
questionList.add(q);
});
showNextQuestion();
}
/**
* 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() {
jButton1 = new javax.swing.JButton();
textField1 = new java.awt.TextField();
label1 = new java.awt.Label();
jScrollPane1 = new javax.swing.JScrollPane();
jTextArea1 = new javax.swing.JTextArea();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("Next");
jButton1.addActionListener(e -> {
showNextQuestion();
});
textField1.setName("\"\""); // NOI18N
textField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
textField1ActionPerformed(evt);
}
});
label1.setText("Answer:");
jTextArea1.setColumns(20);
jTextArea1.setRows(5);
jScrollPane1.setViewportView(jTextArea1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING,
layout.createSequentialGroup().addGap(0, 0, Short.MAX_VALUE)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(textField1, javax.swing.GroupLayout.PREFERRED_SIZE, 53,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 57,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(28, 28, 28))
.addGroup(layout.createSequentialGroup()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 421,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)));
layout.setVerticalGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(
javax.swing.GroupLayout.Alignment.TRAILING,
layout.createSequentialGroup().addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 206,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(textField1, javax.swing.GroupLayout.PREFERRED_SIZE, 30,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton1))
.addContainerGap()));
label1.getAccessibleContext().setAccessibleName("Answer: ");
pack();
}// </editor-fold>
private void textField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
/**
* #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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
// </editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new NewJFrame().setVisible(true);
} catch (IOException ex) {
Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
private java.awt.Label label1;
private java.awt.TextField textField1;
// End of variables declaration
}
Notice that I used a Properties object to load all the keys, and then for each of those lines, I parsed it and created a Question object and add it to a questionList. Also, notice the jButton1.addActionListener(e -> { showNextQuestion(); });. Call showNextQuestion(); method everytime you want the next question, in this case, every time to click the Next button.
I'm not sure what you want to acomplish with this application, is not clear yet, but I simply answered your question on how to show the next question.

First of all, your questions in the file should be in uniform format, I mean we should be able to distinguish between different question and it's options.
Secondly, then you read each question and it's options and store it in an Java Object. Let's say Question object.
Question object might be something like below:-
class Question {
String questionString;
String[] options;
}
Then, after you read each question/options and form an Object, you store these objects in a DoublyLinkedList, so you can easily navigate back and forth when user clicks Previous button or Next button.

How to fix java.lang.StackoverflowError

I'm not sure what the problem with this code is but whenever I run it I get a java.lang.StackOverflowError. How would I fix it? This is what is displayed in the output console of netbeans:
run:
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at sun.awt.Win32GraphicsConfig.getBounds(Native Method)
at sun.awt.Win32GraphicsConfig.getBounds(Win32GraphicsConfig.java:222) at sun.awt.Win32GraphicsConfig.getBounds(Win32GraphicsConfig.java:222)
at java.awt.Window.init(Window.java:497)
at java.awt.Window.<init>(Window.java:536)
at java.awt.Frame.<init>(Frame.java:420)
at java.awt.Frame.<init>(Frame.java:385)
at javax.swing.JFrame.<init>(JFrame.java:180)
code
import java.awt.Color;
import java.awt.Font;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ButtonGroup;
import javax.swing.JOptionPane;
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* #author Nicholas Ferretti
*/
public class Section2 extends javax.swing.JFrame {
Section2 s2Frame = new Section2();
Section3 s3Frame = new Section3();
ResultSet section2Questions;
DB connection = new DB();
/**
* Creates new form Section2Question1
*/
TimerFrame timerFrame;
int timeRemaining = 60;
int s2QuestionNumber = 1;
public Section2() {
this.timerFrame = new TimerFrame(this);
initComponents();
groupButton();
section2QuestionBox.setEditable(false);
s2QuestionNumberLabel.setText("Question "+s2QuestionNumber+":");
try {
section2Questions=connection.queryTbl("SELECT * FROM tblQuestions WHERE Section = 2");
section2Questions.next();
String firstQuestion = section2Questions.getString("Questions");
System.out.println(firstQuestion);
section2QuestionBox.setText(firstQuestion);
String firstAnswers = section2Questions.getString("AllPossibleAnswers");
Scanner scLine = new Scanner(firstAnswers).useDelimiter(",");
while(scLine.hasNext()){
String answer1 = scLine.next();
S2Answer1.setText(answer1);
System.out.println(answer1);
String answer2 = scLine.next();
S2Answer2.setText(answer2);
System.out.println(answer2);
String answer3 = scLine.next();
S2Answer3.setText(answer3);
System.out.println(answer3);
String answer4 = scLine.next();
S2Answer4.setText(answer4);
System.out.println(answer4);
}
} catch (SQLException ex) {
Logger.getLogger(Section1.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Error with SQL firstQuestion");
}
/*boolean t = timerFrame.timer(Section2Timer, timeRemaining);
if(t == false){
JOptionPane.showMessageDialog(null, "Time up for section.");
s2Frame.setVisible(false);
//s3Frame.setVisible(true);
}*/
}
private void groupButton() {
ButtonGroup buttons = new ButtonGroup();
buttons.add(S2Answer2);
buttons.add(S2Answer3);
buttons.add(S2Answer1);
buttons.add(S2Answer4);
}
private void timer() {
try {
Score time = new Score();
int timeRemaining = time.getTime();
while(timeRemaining>0){
Section2Timer.setText(timeRemaining+"");
Section2Timer.setFont(new Font("Serif", Font.BOLD, 32));
Section2Timer.setForeground(Color.RED);
Thread.sleep(1000);
timeRemaining--;
if(timeRemaining==0){
time.setTime(60);
}
time.setTime(timeRemaining);
}
} catch (InterruptedException e) {
e.printStackTrace();
// handle the exception...
// For example consider calling Thread.currentThread().interrupt(); here.
}
}
/**
* 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() {
jLabel7 = new javax.swing.JLabel();
s2QuestionNumberLabel = new javax.swing.JLabel();
jLabel9 = new javax.swing.JLabel();
jScrollPane3 = new javax.swing.JScrollPane();
section2QuestionBox = new javax.swing.JTextArea();
S2Answer1 = new javax.swing.JRadioButton();
S2Answer2 = new javax.swing.JRadioButton();
S2Answer3 = new javax.swing.JRadioButton();
S2Answer4 = new javax.swing.JRadioButton();
nextS2Question = new javax.swing.JButton();
Section2Timer = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel7.setFont(new java.awt.Font("Tahoma", 1, 36)); // NOI18N
jLabel7.setText("SECTION 2:");
s2QuestionNumberLabel.setFont(new java.awt.Font("Tahoma", 1, 18)); // NOI18N
s2QuestionNumberLabel.setText("QUESTION 1:");
jLabel9.setText("Answers:");
section2QuestionBox.setColumns(20);
section2QuestionBox.setRows(5);
section2QuestionBox.setText("At a conference, 12 memeber shook hands with each other \nbefore & after the meeting. How many total number of\nhand shakes occurred?");
jScrollPane3.setViewportView(section2QuestionBox);
S2Answer1.setText("Monday");
S2Answer1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
S2Answer1ActionPerformed(evt);
}
});
S2Answer2.setText("Tuesday");
S2Answer2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
S2Answer2ActionPerformed(evt);
}
});
S2Answer3.setText("Wednesday");
S2Answer3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
S2Answer3ActionPerformed(evt);
}
});
S2Answer4.setText("Friday");
S2Answer4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
S2Answer4ActionPerformed(evt);
}
});
nextS2Question.setText("Next");
nextS2Question.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
nextS2QuestionActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel7, javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGap(125, 125, 125)
.addComponent(s2QuestionNumberLabel)))
.addGap(0, 0, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGap(217, 217, 217)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane3, javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel9)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(S2Answer1)
.addGap(53, 53, 53)
.addComponent(S2Answer2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 56, Short.MAX_VALUE)
.addComponent(S2Answer3)
.addGap(45, 45, 45)
.addComponent(S2Answer4))
.addComponent(nextS2Question, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))
.addGap(139, 139, 139)
.addComponent(Section2Timer, javax.swing.GroupLayout.PREFERRED_SIZE, 101, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(Section2Timer, javax.swing.GroupLayout.PREFERRED_SIZE, 54, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel7, javax.swing.GroupLayout.PREFERRED_SIZE, 74, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(0, 0, 0)
.addComponent(s2QuestionNumberLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 40, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jScrollPane3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(50, 50, 50)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel9)
.addComponent(S2Answer1)
.addComponent(S2Answer2)
.addComponent(S2Answer3)
.addComponent(S2Answer4))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 140, Short.MAX_VALUE)
.addComponent(nextS2Question)
.addGap(125, 125, 125))
);
pack();
}// </editor-fold>
String answer = "";
private void S2Answer1ActionPerformed(java.awt.event.ActionEvent evt) {
answer = S2Answer1.getText();
}
private void S2Answer2ActionPerformed(java.awt.event.ActionEvent evt) {
answer = S2Answer2.getText();
}
private void S2Answer3ActionPerformed(java.awt.event.ActionEvent evt) {
answer = S2Answer3.getText();
}
private void S2Answer4ActionPerformed(java.awt.event.ActionEvent evt) {
answer = S2Answer4.getText();
}
private void nextS2QuestionActionPerformed(java.awt.event.ActionEvent evt) {
Score score = new Score();
try {
String actualAnswer = section2Questions.getString("Answer");
int currentScore = score.getS2Score();
if(answer.equalsIgnoreCase(actualAnswer)){
currentScore+=5;
score.setS2Score(currentScore);
}
} catch (SQLException ex) {
Logger.getLogger(Section1.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Error in Next Question method");
}
if(s2QuestionNumber ==4){
int timeLeft = score.getTime();
int currentBonusPoints = score.getBonusPoints();
score.setBonusPoints(timeLeft+currentBonusPoints);
s2Frame.setVisible(false);
s3Frame.setVisible(true);
}
try {
section2Questions.next();
String nextQuestion = section2Questions.getString("Questions");
section2QuestionBox.setText(nextQuestion);
s2QuestionNumber++;
s2QuestionNumberLabel.setText("Question "+s2QuestionNumber+":");
} catch (SQLException ex) {
Logger.getLogger(Section1.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Error in Next Question method");
}
}
/**
* #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(Section2.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Section2.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Section2.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Section2.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Section2().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JRadioButton S2Answer1;
private javax.swing.JRadioButton S2Answer2;
private javax.swing.JRadioButton S2Answer3;
private javax.swing.JRadioButton S2Answer4;
private javax.swing.JLabel Section2Timer;
private javax.swing.JLabel jLabel7;
private javax.swing.JLabel jLabel9;
private javax.swing.JScrollPane jScrollPane3;
private javax.swing.JButton nextS2Question;
private javax.swing.JLabel s2QuestionNumberLabel;
private javax.swing.JTextArea section2QuestionBox;
// End of variables declaration
}

The very first line in your class Section2 would cause the problem.
You have, Section2 s2Frame = new Section2();, which means, every time an object is created for Section2 you want to create another object of Section2 (which will create another object... and sooooooooo on...)
Hence the stackoverflow exception...

org.apache.poi.openxml4j.exceptions.InvalidFormatException

I have created a search tool in java that reads doc and docx files. First, the user have to select a folder that contain the word documents. The program works fine however when I select desktop as the folder it gives the following error: org.apache.poi.openxml4j.exceptions.InvalidFormatException: Package should contain a content type part [M1.13]
Here is my code:
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.*;
import java.util.Scanner;
import javax.swing.JOptionPane;
import java.util.ArrayList;
import org.apache.poi.xwpf.extractor.XWPFWordExtractor;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.hwpf.HWPFDocument;
import org.apache.poi.hwpf.extractor.WordExtractor;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/*
* Main.java
*
* Created on Jul 4, 2014, 8:19:21 AM
*/
/**
*
* #author Yağız
*/
public class search extends javax.swing.JFrame {
Boolean check = true;
File[] filelist;
/** Creates new form Main */
public search() {
initComponents();
setIcon();
}
/** 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() {
bindingGroup = new org.jdesktop.beansbinding.BindingGroup();
jFrame1 = new javax.swing.JFrame();
jMenuBar1 = new javax.swing.JMenuBar();
jMenu1 = new javax.swing.JMenu();
jMenu2 = new javax.swing.JMenu();
label1 = new java.awt.Label();
jTextField1 = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
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)
);
jMenu1.setText("File");
jMenuBar1.add(jMenu1);
jMenu2.setText("Edit");
jMenuBar1.add(jMenu2);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
org.jdesktop.beansbinding.Binding binding = org.jdesktop.beansbinding.Bindings.createAutoBinding(org.jdesktop.beansbinding.AutoBinding.UpdateStrategy.READ_WRITE, jFrame1, org.jdesktop.beansbinding.ELProperty.create("CV Search"), this, org.jdesktop.beansbinding.BeanProperty.create("title"));
bindingGroup.addBinding(binding);
label1.setText("Keyword:");
jButton1.setText("Find");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("Select Folder");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(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()
.addGap(29, 29, 29)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 56, Short.MAX_VALUE)
.addComponent(jButton1))
.addGroup(layout.createSequentialGroup()
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 140, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(29, 29, 29))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField1, 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(jButton2)
.addComponent(jButton1))
.addGap(37, 37, 37))
);
bindingGroup.bind();
java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
setBounds((screenSize.width-278)/2, (screenSize.height-158)/2, 278, 158);
jFrame1.getRootPane().setDefaultButton(jButton1);
}// </editor-fold>
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
//Select Folder Button
try{
JFileChooser fc = new JFileChooser();
fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
fc.showOpenDialog(null);
if(fc.getSelectedFile()==null){
check = false;
}
else
{
File folder = new File(fc.getSelectedFile().getPath());
filelist = folder.listFiles();
if( filelist.length == 0 ){
// dialog: folder is empty
check = false;
}
else
{
check = true;
}
}
}catch(Exception e){
e.printStackTrace();
JOptionPane.showMessageDialog(null, "Error");
}
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
//Find button for finding the word in word documents in the selected folder
String keyword = jTextField1.getText();
int count=0;
while (! check ) {
JOptionPane.showMessageDialog(null, "Select a Folder!");
return;
}
if(keyword.equals("")){
JOptionPane.showMessageDialog(null, "No keyword found!");
return;
}
ArrayList result = new ArrayList();
try
{
for( int i=0; i < filelist.length; i++){
// maybe also .doc?
if( filelist[i].getName().endsWith( ".docx" ) ){
count++;
XWPFDocument input = new XWPFDocument(new FileInputStream(filelist[i]));
XWPFWordExtractor extract = new XWPFWordExtractor(input);
Scanner scan = new Scanner(extract.getText());
while(scan.hasNext())
{
String word = scan.next();
if( keyword.equalsIgnoreCase(word) ) {
result.add(filelist[i].getName().replace(".docx",""));
break;
}
}
}
else if(filelist[i].getName().endsWith( ".doc" )){
HWPFDocument inputdoc = new HWPFDocument(new FileInputStream(filelist[i]));
WordExtractor extract = new WordExtractor(inputdoc);
Scanner scan = new Scanner(extract.getText());
while(scan.hasNext())
{
String word = scan.next();
if( keyword.equalsIgnoreCase(word) ) {
result.add(filelist[i].getName().replace(".doc",""));
break;
}
}
}
else
continue;
}
if( count == 0 ){
JOptionPane.showMessageDialog(null,"Selected folder must contain word documents");
return;
}
//...
if(result.isEmpty()){
JOptionPane.showMessageDialog(null,"No match found!");
return;
}
else {
StringBuilder sb = new StringBuilder();
for( int j = 0; j < result.size(); j++){
sb.append( result.get(j) ).append( "\n" );
}
JOptionPane.showMessageDialog( null, sb.toString(), "Results", JOptionPane.INFORMATION_MESSAGE );
}
} catch (Exception e){
e.printStackTrace();
JOptionPane.showMessageDialog(null, "Error!");
}
}
private void jTextField1KeyPressed(java.awt.event.KeyEvent evt) {
if( evt.getKeyCode() == KeyEvent.VK_ENTER ){
jButton1.doClick();
}
}
/**
* #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(search.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(search.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(search.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(search.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new search().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JFrame jFrame1;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JTextField jTextField1;
private java.awt.Label label1;
private org.jdesktop.beansbinding.BindingGroup bindingGroup;
// End of variables declaration
private void setIcon(){
setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("icon.png")));
}
}
What does this error mean and when does it occur? Can anyone help with my situation? Thanks

How do I Calculate the Average using the CalculateButton with following code for a KDRCalculator Program

In the following code I don't know how to find the average using the Calculate Button. I have managed to read the text in through Text fields for the values but i don't know how to make the program calculate the average and print it in the textfield once the Calculate Button has been clicked.
import java.util.Scanner;
public class KdrCalGui extends javax.swing.JFrame {
/**
* Creates new form KdrCalGui
*/
public KdrCalGui() {
initComponents();
double kills;
double deaths;
double subtotal;
double roundnumber;
}
/**
* 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() {
KillsValue = new javax.swing.JTextField();
KillsLabel = new javax.swing.JLabel();
DeathsValue = new javax.swing.JLabel();
DeathsLabel = new javax.swing.JTextField();
CalculateButton = new javax.swing.JButton();
jLabel3 = new javax.swing.JLabel();
Display = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
KillsValue.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
KillsValueActionPerformed(evt);
}
});
KillsLabel.setText("Kills");
DeathsValue.setText("Deaths");
DeathsLabel.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
DeathsLabelActionPerformed(evt);
}
});
CalculateButton.setText("Calculate");
CalculateButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
CalculateButtonActionPerformed(evt);
}
});
jLabel3.setText("Your KDR");
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(39, 39, 39)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.CENTER)
.addComponent(CalculateButton, javax.swing.GroupLayout.PREFERRED_SIZE, 86, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(DeathsLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 66, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(DeathsValue)
.addComponent(KillsValue, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(KillsLabel))
.addGap(113, 113, 113)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.CENTER)
.addComponent(Display, javax.swing.GroupLayout.PREFERRED_SIZE, 91, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel3))
.addContainerGap(31, Short.MAX_VALUE))
);
layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {DeathsLabel, KillsValue});
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addComponent(KillsLabel)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(KillsValue, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(DeathsValue)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(DeathsLabel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(25, 25, 25)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(Display)))
.addGap(36, 36, 36)
.addComponent(CalculateButton, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(50, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void DeathsLabelActionPerformed(java.awt.event.ActionEvent evt) {
DeathsLabel.setText(DeathsLabel.getText());
double deaths;
Scanner sc= new Scanner(System.in);
deaths=sc.nextInt();
}
private void KillsValueActionPerformed(java.awt.event.ActionEvent evt) {
KillsLabel.setText(KillsLabel.getText());
double kills;
Scanner sc=new Scanner(System.in);
kills=sc.nextInt();
}
THIS IS THE CALCULATE BUTTON.
private void CalculateButtonActionPerformed(java.awt.event.ActionEvent evt) {
}
/**
* #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(KdrCalGui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(KdrCalGui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(KdrCalGui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(KdrCalGui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new KdrCalGui().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton CalculateButton;
private javax.swing.JTextField DeathsLabel;
private javax.swing.JLabel DeathsValue;
private javax.swing.JTextField Display;
private javax.swing.JLabel KillsLabel;
private javax.swing.JTextField KillsValue;
private javax.swing.JLabel jLabel3;
// End of variables declaration
}

CalculateButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
if (evt.getSource() == CalculateButton) {
// not sure what exactly you're trying to average
// but if it's the kills and deaths value, then...
int k = Integer.parseInt(KillsValue.getText());
int d = Integer.parseInt(DeathsValue.getText());
Display.setText((k+d)/2);
// think about adding exception handling in case they enter a noninteger
// also you switched the names of the TextField and Label in the initComponents()
}
}
});

Netbeans Java CRUD application with custom swing interface

i'm trying to build a java application with an embedded database. It will be very similiar to a CRUD application and i looked deeply in many tutorials provided for oracle and netbeans like this ones:
http://platform.netbeans.org/tutorials/nbm-crud.html
http://netbeans.org/kb/70/java/gui-db.html
However, this build automatically a default interface based on just crud actions and that's not what i want. I pretend to customize by myself all the interface and when need, access the derby embedded database to execute some operations.
In the mean time i just have two .java files. The JFrame one which contains the code generated by the elements added on the design menu:
package interface_aquitex;
import aquitex.Aquitex;
import javax.swing.JOptionPane;
public class design_aquitex extends javax.swing.JFrame {
/**
* Creates new form design_aquitex
*/
public design_aquitex() {
initComponents();
}
/**
* 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() {
jFrame1 = new javax.swing.JFrame();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jTextField1 = new javax.swing.JTextField();
jTextField2 = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
jLabel3 = new javax.swing.JLabel();
jButton2 = new javax.swing.JButton();
jMenuBar1 = new javax.swing.JMenuBar();
jMenu1 = new javax.swing.JMenu();
jMenuItem1 = new javax.swing.JMenuItem();
jMenu2 = new javax.swing.JMenu();
jFrame1.setMinimumSize(new java.awt.Dimension(400, 400));
jLabel1.setText("Nome:");
jLabel2.setText("Idade:");
jTextField1.setName(""); // NOI18N
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(evt);
}
});
jTextField1.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
jTextField1PropertyChange(evt);
}
});
jTextField1.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent evt) {
jTextField1KeyPressed(evt);
}
});
jButton1.setText("Inserir");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jLabel3.setText("Dados");
jButton2.setText("Listar");
javax.swing.GroupLayout jFrame1Layout = new javax.swing.GroupLayout(jFrame1.getContentPane());
jFrame1.getContentPane().setLayout(jFrame1Layout);
jFrame1Layout.setHorizontalGroup(
jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jFrame1Layout.createSequentialGroup()
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jFrame1Layout.createSequentialGroup()
.addGap(26, 26, 26)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGap(37, 37, 37)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 56, Short.MAX_VALUE)
.addComponent(jTextField2)))
.addGroup(jFrame1Layout.createSequentialGroup()
.addGap(57, 57, 57)
.addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 64, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 92, Short.MAX_VALUE)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jButton2)
.addComponent(jButton1))
.addGap(94, 94, 94))
);
jFrame1Layout.setVerticalGroup(
jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jFrame1Layout.createSequentialGroup()
.addGap(24, 24, 24)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(5, 5, 5)
.addComponent(jButton1)
.addGap(4, 4, 4)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(88, 88, 88)
.addGroup(jFrame1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 37, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton2))
.addContainerGap(79, Short.MAX_VALUE))
);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jMenu1.setText("File");
jMenuItem1.setText("jMenuItem1");
jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jMenuItem1ActionPerformed(evt);
}
});
jMenu1.add(jMenuItem1);
jMenuBar1.add(jMenu1);
jMenu2.setText("Edit");
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)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 279, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
public String getjTextField1(){
JOptionPane.showMessageDialog(null,jTextField1.getText());
return jTextField1.getText();
}
public int getjTextField2(){
int idade;
idade = Integer.parseInt(jTextField2.getText());
System.out.println(idade);
return idade;
}
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {
jFrame1.setVisible(true);
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
Aquitex a = new Aquitex();
a.saveRecord();
}
private void jTextField1PropertyChange(java.beans.PropertyChangeEvent evt) {
// TODO add your handling code here:
}
private void jTextField1KeyPressed(java.awt.event.KeyEvent evt) {
JOptionPane.showMessageDialog(null,jTextField1.getText());
}
/**
* #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(design_aquitex.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(design_aquitex.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(design_aquitex.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(design_aquitex.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new design_aquitex().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JFrame jFrame1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem1;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
// End of variables declaration
}
and the one with a class created by me:
package aquitex;
import interface_aquitex.design_aquitex;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
public class Aquitex extends JFrame{
private static PreparedStatement stmtSaveNewRecord=null;
private static Connection dbConnection = null;
String tabelaExp =
"CREATE table APP.Alunos ("+
" ID INTEGER NOT NULL"+
" PRIMARY KEY GENERATED ALWAYS AS IDENTITY "+
" (START WITH 1, INCREMENT BY 1),"+
"FIRSTNAME VARCHAR(30),"+
"AGE INT )";
private void setDBSystemDir() {
// Decide on the db system directory: <userhome>/.aquitex/
String userHomeDir = System.getProperty("user.home", ".");
String systemDir = userHomeDir + "/.aquitex";
// Set the db system directory.
System.setProperty("derby.system.home", systemDir);
}
private boolean createTables(Connection dbConnection) {
boolean bCreatedTables = false;
Statement statement = null;
try {
statement = dbConnection.createStatement();
statement.execute(tabelaExp);
bCreatedTables = true;
} catch (SQLException ex) {
ex.printStackTrace();
}
return bCreatedTables;
}
public int saveRecord() {
design_aquitex da = new design_aquitex();
try {
stmtSaveNewRecord = dbConnection.prepareStatement(
"INSERT INTO APP.Alunos " +
" (FIRSTNAME, AGE) " +
"VALUES (?, ?)",
Statement.RETURN_GENERATED_KEYS);
} catch (SQLException ex) {
Logger.getLogger(Aquitex.class.getName()).log(Level.SEVERE, null, ex);
}
int id = -1;
try {
stmtSaveNewRecord.clearParameters();
stmtSaveNewRecord.setString(1, da.getjTextField1());
stmtSaveNewRecord.setInt(2, da.getjTextField2());
int rowCount = stmtSaveNewRecord.executeUpdate();
ResultSet results = stmtSaveNewRecord.getGeneratedKeys();
if (results.next()) {
id = results.getInt(1);
}
} catch(SQLException sqle) {
sqle.printStackTrace();
}
return id;
}
public static void main(String[] args) {
// TODO code application logic here
String userHomeDir = System.getProperty("user.home", ".");
String systemDir = userHomeDir + "/.aquitex";
// Set the db system directory.
System.setProperty("derby.system.home", systemDir);
String strUrl = "jdbc:derby:aquitex_db;create=true";
Properties props = new Properties();
props.put("user", "adm_aquitex");
props.put("password", "pass_aquitex");
try {
dbConnection = DriverManager.getConnection(strUrl, props);
} catch (SQLException ex) {
Logger.getLogger(Aquitex.class.getName()).log(Level.SEVERE, null, ex);
}
//Aquitex a = new Aquitex();
//a.createTables(dbConnection);
design_aquitex da = new design_aquitex();
da.setVisible(true);
}
}
For now, what i really need is some lights in how to separate the interface from the database i mean, use a "class" or something between them so that they don't "contact" each other.
And my other question is about the tables that i have on the database. Will they need a class.java file for each of them? And what about the Entity Manager Class presented in this tutorial:
http://platform.netbeans.org/tutorials/nbm-crud.html
Will i need to use it? I'm using derby database.
Sory for a so long questio, but i'm a bit lost at the moment in how to make the structure in what is supposed to be a java crud desktop application with a custom interface, and in how to make the layers ("swing","db" and the one that separates them") connect between each other.

1) your first file (what is it's name?) should have all the GUI stuff.
2) Your second file ("Aquitex.java"?) should not extend from JFrame, and should not necessarily have any GUI stuff.
3) Your main form will create an instance of "Aquitex".
4) UI event handlers in the first class will call public methods in the second.