Program: 78392
Project: 78392
Buggy source:
/** 
 * inizializza le componenti dell'interfaccia
 */
private void initComponents(){
  panelData.setLayout(new GridLayout(3,1,20,30));
  panelData.setBorder(BorderFactory.createTitledBorder("String_Node_Str"));
  panelData.add(labelCurrentPassword);
  panelData.add(textCurrentPassword);
  panelData.add(labelNewPassword);
  panelData.add(textNewPassword);
  panelData.add(labelPasswordConf);
  panelData.add(textPasswordConf);
  panelOut.add(panelData,BorderLayout.NORTH);
  panelOut.add(panelButton,BorderLayout.SOUTH);
  add(panelOut);
  panelButton.setLayout(new GridLayout(1,2,10,5));
  panelButton.setBorder(BorderFactory.createEmptyBorder(30,10,10,10));
  panelButton.add(buttonCancel,BorderLayout.SOUTH);
  panelButton.add(buttonConfirm,BorderLayout.SOUTH);
  ActionListener changepassword=new ActionListener(){
    @Override public void actionPerformed(    ActionEvent passwordAe){
      if (passwordAe.getActionCommand().equals("String_Node_Str")) {
        currentPassword="String_Node_Str";
        newPassword="String_Node_Str";
        confirmPassword="String_Node_Str";
        currentPassword=readPassword(textCurrentPassword.getPassword());
        newPassword=readPassword(textNewPassword.getPassword());
        confirmPassword=readPassword(textPasswordConf.getPassword());
        if (currentPassword == "String_Node_Str" || newPassword == "String_Node_Str" || confirmPassword == "String_Node_Str") {
          JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.ERROR_MESSAGE);
        }
 else         if (checkPassword(currentPassword)) {
          if (!(getSpecialCharacterCount(newPassword))) {
            if (changePasswordFields(newPassword,confirmPassword)) {
              JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.INFORMATION_MESSAGE);
              dispose();
            }
          }
 else {
            JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.ERROR_MESSAGE);
          }
        }
      }
      if (passwordAe.getActionCommand().equals("String_Node_Str")) {
        dispose();
      }
    }
  }
;
  buttonCancel.addActionListener(changepassword);
  buttonConfirm.addActionListener(changepassword);
}

Fixed version (ground truth):
/** 
 * inizializza le componenti dell'interfaccia
 */
private void initComponents(){
  panelData.setLayout(new GridLayout(3,1,20,30));
  panelData.setBorder(BorderFactory.createTitledBorder("String_Node_Str"));
  panelData.add(labelCurrentPassword);
  panelData.add(textCurrentPassword);
  panelData.add(labelNewPassword);
  panelData.add(textNewPassword);
  panelData.add(labelPasswordConf);
  panelData.add(textPasswordConf);
  panelOut.add(panelData,BorderLayout.NORTH);
  panelOut.add(panelButton,BorderLayout.SOUTH);
  add(panelOut);
  panelButton.setLayout(new GridLayout(1,2,10,5));
  panelButton.setBorder(BorderFactory.createEmptyBorder(30,10,10,10));
  panelButton.add(buttonCancel,BorderLayout.SOUTH);
  panelButton.add(buttonConfirm,BorderLayout.SOUTH);
  ActionListener changepassword=new ActionListener(){
    @Override public void actionPerformed(    ActionEvent passwordAe){
      if (passwordAe.getActionCommand().equals("String_Node_Str")) {
        currentPassword="String_Node_Str";
        newPassword="String_Node_Str";
        confirmPassword="String_Node_Str";
        currentPassword=readPassword(textCurrentPassword.getPassword());
        newPassword=readPassword(textNewPassword.getPassword());
        confirmPassword=readPassword(textPasswordConf.getPassword());
        if (currentPassword == "String_Node_Str" || newPassword == "String_Node_Str" || confirmPassword == "String_Node_Str") {
          JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.ERROR_MESSAGE);
        }
 else         if (checkPassword(currentPassword)) {
          if (!(getSpecialCharacterCount(newPassword))) {
            if (changePasswordFields(newPassword,confirmPassword)) {
              JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.INFORMATION_MESSAGE);
              guiChangePassword.dispatchEvent(new WindowEvent(guiChangePassword,WindowEvent.WINDOW_CLOSING));
            }
          }
 else {
            JOptionPane.showMessageDialog(new JFrame(),"String_Node_Str","String_Node_Str",JOptionPane.ERROR_MESSAGE);
          }
        }
      }
    }
  }
;
  buttonCancel.addActionListener(e -> guiChangePassword.dispatchEvent(new WindowEvent(guiChangePassword,WindowEvent.WINDOW_CLOSING)));
  buttonConfirm.addActionListener(changepassword);
}