JTextFields sometimes still contains old values even setText("") performed

Question

I have a program which let user enter 3 JTextFields : hostname, userid, password, and one JButton. When the button is clicked, below function will be executed to get the value of the JTextField, then relevant function will be called.
My problem is when I run the program, sometimes it will get the "previous" value, sometimes it works correctly. I make sure all JTextFields values will be cleared each time, but no help. Here is part of my code:
    private void sendActionPerformed(java.awt.event.ActionEvent evt) {                                    
        String hn = hostname.getText();
        String ln = login.getText();
        String pd = password.getText();
        hostname.setText("");
        login.setText("");
        password.setText("");
        result.setText("");
        p  = new Process();
        p.setPara(hn,ln,pd);
        result.setText(p.sendmail());
        p = null;      
    }Does anyone have ideas or suggestion? Thx.

Answer 1

Ok, there are 2 files, the main class is the Email.java file.
Email.java
public class Email extends javax.swing.JFrame {
    /** Creates new form Email */
    public Email() {
        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.
    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">
    private void initComponents() {
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        hostname = new javax.swing.JTextField();
        login = new javax.swing.JTextField();
        password = new javax.swing.JTextField();
        send = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        result = new javax.swing.JTextArea();
        jLabel4 = new javax.swing.JLabel();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jLabel1.setText("HostName (blank for localhost):");
        jLabel2.setText("Login:");
        jLabel3.setText("Password:");
        hostname.setText("smtp.test.com");
        login.setText("[email protected]");
        login.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                loginActionPerformed(evt);
        password.setText("mypassword");
        send.setText("Send");
        send.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                sendActionPerformed(evt);
        result.setColumns(20);
        result.setEditable(false);
        result.setLineWrap(true);
        result.setRows(5);
        jScrollPane1.setViewportView(result);
        jLabel4.setText("Result:");
        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, false)
                            .addComponent(jLabel2)
                            .addComponent(jLabel3)
                            .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 159, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                    .addComponent(hostname, javax.swing.GroupLayout.Alignment.TRAILING)
                                    .addComponent(login, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 249, Short.MAX_VALUE)))
                            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, 249, javax.swing.GroupLayout.PREFERRED_SIZE)))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel4)
                        .addGap(161, 161, 161)
                        .addComponent(send))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 441, Short.MAX_VALUE)))
                .addGap(123, 123, 123))
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addGap(24, 24, 24)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(hostname, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 12, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(login, 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.TRAILING)
                    .addComponent(jLabel3)
                    .addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(20, 20, 20)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel4)
                    .addComponent(send))
                .addGap(20, 20, 20)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 132, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(110, 110, 110))
        pack();
    }// </editor-fold>
    private void sendActionPerformed(java.awt.event.ActionEvent evt) {                                    
        String hn = hostname.getText();
        String ln = login.getText();
        String pd = password.getText();
        //result.setText("hn:"+hn+",ln:"+ln+"pd:"+pd);
        hostname.setText("");
        login.setText("");
        password.setText("");
        result.setText("");
        p  = new Process();
        p.setPara(hn,ln,pd);
        result.setText(p.sendmail());
        p = null;
     * @param args the command line arguments
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Email().setVisible(true);
    // Variables declaration - do not modify
    private javax.swing.JTextField hostname;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextField login;
    private javax.swing.JTextField password;
    private javax.swing.JTextArea result;
    private javax.swing.JButton send;
    // End of variables declaration
    private Process p;
Process.java
import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
import java.io.*;
import java.util.Random;
public class Process {
private Boolean shouldAuth = false;
private String SMTP_HOST_NAME = "";
private String SMTP_AUTH_USER = "";
private String SMTP_AUTH_PWD  = "";
private String emailMsgTxt;
private String emailSubjectTxt;
private String emailFromAddress;
private Boolean isError = false;
private String output = "";
private Random ran;
  public Process(){}
  public void setPara(String hostname, String username, String password){
      if((hostname.equalsIgnoreCase(""))||(hostname == null)){
        SMTP_HOST_NAME = "localhost";
            shouldAuth = false;
      }else{
          shouldAuth = true;
          SMTP_HOST_NAME = (hostname == "") ? "" : hostname;
          SMTP_AUTH_USER = (username == "") ? "" : username;
          SMTP_AUTH_PWD = (password == "") ? "" : password;
      emailFromAddress = "[email protected]";
      emailSubjectTxt = "testing email from abchk";
      emailMsgTxt = "This is a testing message to test the JavaMail."; 
  private class SMTPAuthenticator extends javax.mail.Authenticator{
      public PasswordAuthentication getPasswordAuthentication()
          String username = SMTP_AUTH_USER;
          String password = SMTP_AUTH_PWD;
          return new PasswordAuthentication(username, password);
  public String debug(){
      String tmp = "Output is: ";
      ran = new Random();
      Integer no = ran.nextInt(100);
      return tmp + no.toString();        
  public String sendmail(){
    //Set the host smtp address
    Properties props = new Properties();
    props.put("mail.smtp.host", SMTP_HOST_NAME);
    props.put("mail.smtp.auth", (shouldAuth==true)? "true":"false");
    Session sess;
    if(shouldAuth==true){
        Authenticator auth = new SMTPAuthenticator();
        sess = Session.getDefaultInstance(props, auth);
        //System.out.println("true");
    }else{
        sess = Session.getInstance(props);
        //sess = Session.getDefaultInstance(props, null);
        //System.out.println("false");
    sess.setDebug(false);
    //Create a message
    Message msg = new MimeMessage(sess);
    //Set message
    String tmp = "";
    try{
      msg.setFrom(new InternetAddress(emailFromAddress));
      msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected]"));
      msg.setSubject(emailSubjectTxt);
      msg.setText(emailMsgTxt);
      Transport.send(msg);
    }catch(SendFailedException sfe){
      tmp += "SendFailedException:"+sfe.toString()+"\r\n";
    }catch(AddressException ae){
      tmp += "AddressException:" +ae.toString()+"\r\n";
    }catch(MessagingException me){
      tmp += "MessagingException:" +me.toString()+"\r\n";
    }catch(Exception e){  
      tmp += "Exception:" + e.toString()+"\r\n";       
    if(tmp.equalsIgnoreCase("")){
      tmp += "Email will be successfully delivered IF(*) information is correct.";
    String more = debug();
    return tmp + "\r\n" + more;
}the problem was described as the 1st post, after pressing the send button, the later output message MAY NOT reflect the result, that means even try catch catches the error, the output message still MAY display the previous message, which will misleads the user.