Question

I have a created a simple applet which sends mail by using smtp.gmail.com on clicking a button “Send Mail”. It runs perfectly from Eclipse. From eclipse I Run it as Java Applet and it sends mail without any error.

But when run from the appletviewer, outside the eclipse it throws an error: java.security.AccessControlException: access denied (java.net.SocketPermission smtp.gmail.com resolve)

I have signed the JAR of my program. After signing, it sends the mail if applet is run from Internet Explorer but throws the above error if applet is run from Google Chrome browser or appletviewer.

Command to make a keystore:
“c:\Program Files\Java\jre6\bin\keytool.exe” -genkey -alias -validity 365 -keystore -keyalg rsa

Command to sign the jar:
\bin\jarsigner.exe -signedjar -keystore

JAR was formed by exporting the same from Eclipse only.

Command to run the applet:
“c:\Program Files\Java\jdk1.6.0_27\bin\appletviewer.exe”

Please have a look into code and let me know where I am doing wrong…

Code for applet

package in.appletmail;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;

@SuppressWarnings("serial")
public class SendMailApplet extends JApplet
{
    boolean isStandalone = false;
    JPanel jPanel1 = new JPanel();
    JTextField jTextField1 = new JTextField();
    JButton jButton = new JButton("Send Mail");
    GridBagLayout gridBagLayout1 = new GridBagLayout();

    // Construct the applet
    public SendMailApplet()
    {
        // TODO Auto-generated constructor stub
    }

    // Initialize the applet
    public void init()
    {
        try
        {
            jbInit();
        } catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    // Initializing the components
    private void jbInit() throws Exception
    {
        this.setSize(new Dimension(500, 200));
        jPanel1.setLayout(gridBagLayout1);

        jTextField1.setText("First Applet");
        this.getContentPane().add(jPanel1, BorderLayout.CENTER);
        jPanel1.add(jTextField1, new GridBagConstraints(0, 0, 1, 1, 1.0, 0.0,
                GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,
                new Insets(140, 128, 139, 132), 77, 0));

        jPanel1.add(jButton, new GridBagConstraints(0, 0, 1, 1, 1.0, 0.0,
                GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,
                new Insets(140, 128, 200, 132), 77, 0));


        final String mailStatus = "Testing Applet Viewer";
        jTextField1.setText(mailStatus);

        jButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                try
                {
                    SendMail.mailVariable("Test mail from applet");
                    jTextField1.setText("Mail Send");
                } catch (Exception e1)
                {
                    jTextField1.setText(e1.toString());
                }

            }
        });
        // jTextField1.setText("Mail Send");
    }

    // Start the applet
    public void start()
    {

    }

    // Stop the applet
    public void stop()
    {

    }

    // Delete the applet
    public void destroy()
    {

    }

    // Fetch applet information
    public String getAppletInfo()
    {
        return "Applet-Information";
    }
}

Code to Send Mail

package in.appletmail;

import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public final class SendMail
{
    private static final String SMTP_HOST_NAME = "smtp.gmail.com";
    private static final String SMTP_PORT = "587";
    private static final String SMTP_AUTH_USER = "username";
    private static final String SMTP_AUTH_PWD = "pass";

    private static final String emailMsgTxt = "Testing mail from Applet, Test again";
    private static final String emailSubjectTxt = "Test mail from Applet via Google";
    private static final String emailFromAddress = "[e-mail]";

    // Add List of Email address to who email needs to be sent to
    private static final String[] emailList = { "[e-mail]" };

    public static String testFunctionCall()
    {
        return "Mailing function will be called";
    }

    public static String mailVariable(String variableValue)
            throws MessagingException
    {
        SendMail smtpMailSender = new SendMail();
        return smtpMailSender.postMail(emailList, emailSubjectTxt, emailMsgTxt
                + "\n variable value:  " + variableValue, emailFromAddress);
    }

    public String postMail(String recipients[], String subject, String message,
            String from) throws MessagingException
    {
        StringBuffer status = new StringBuffer();
        boolean debug = false;

        // Set the host smtp address
        Properties props = new Properties();
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", SMTP_HOST_NAME);
        props.put("mail.smtp.port", SMTP_PORT);
        props.put("mail.smtp.auth", "true");

        Authenticator auth = new SMTPAuthenticator();
        Session session = Session.getDefaultInstance(props, auth);

        session.setDebug(debug);
        status.append("Session set;");
        // create a message
        Message msg = new MimeMessage(session);

        // set the from and to address
        InternetAddress addressFrom = new InternetAddress(from);
        msg.setFrom(addressFrom);

        InternetAddress[] addressTo = new InternetAddress[recipients.length];
        for (int i = 0; i < recipients.length; i++)
        {
            addressTo[i] = new InternetAddress(recipients[i]);
        }
        msg.setRecipients(Message.RecipientType.TO, addressTo);
        status.append("Recipients set;");

        // Setting the Subject and Content Type
        msg.setSubject(subject);
        msg.setContent(message, "text/plain");
        status.append("Subject and Content set;");
        Transport.send(msg);
        status.append("Mail send;");
        return status.toString();
    }

    /**
     * SimpleAuthenticator is used to do simple authentication when the SMTP
     * server requires it.
     */
    private class SMTPAuthenticator extends Authenticator
    {

        public PasswordAuthentication getPasswordAuthentication()
        {
            String username = SMTP_AUTH_USER;
            String password = SMTP_AUTH_PWD;
            return new PasswordAuthentication(username, password);
        }
    }
}

HTML to call the applet:

<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>ABC</title>
</head>
<body bgcolor="#CCCCCC">

<table border="0" cellpadding="0" cellspacing="0" width="144" >
  <tr>
    <td width="10%" height="25" style= "height:25">Powered by Xpace :)
    </td>
    <td width="90%"style= "height:25">
    <APPLET CODEBASE="E:\Gunjan\Workspace\TestAppletExecution\Signed\"
        ARCHIVE="TestApplet.jar, mail.jar"
        CODE="in.appletmail.SendMailApplet.class"
        NAME="Send Mail"
        MAYSCRIPT
        WIDTH="750"
        HEIGHT="350"
        HSPACE="0" VSPACE="0" ALIGN="top">        
    </APPLET>
    </td>
  </tr>
</table>
</body>


</html>

Answer 1

The Applet runs in a sandbox with some restrictions, you have to configure the file jre/lib/security/java.policy adding the line:

permission java.net.SocketPermission "smtp.gmail.com:587", "listen,resolve";