Question

I created a google web application from which I want to send emails. I’ve created the following method for sending mail which works just fine.

public void send(String recipient) throws Exception {
    Properties props = new Properties();

    props.put("mail.transport.protocol", "smtps");
    props.put("mail.smtps.host", SMTP_HOST_NAME);
    props.put("mail.smtps.auth", "true");
    props.put("mail.smtps.quitwait", "false");

    Session mailSession = Session.getDefaultInstance(props);
    mailSession.setDebug(true);
    Transport transport = mailSession.getTransport();

    MimeMessage message = new MimeMessage(mailSession);
    message.setSubject(MESSAGE_SUBJECT);
    message.setContent(MESSAGE_BODY, "text/plain");

    message.addRecipient(Message.RecipientType.TO, new InternetAddress(
            recipient));

    transport.connect(SMTP_HOST_NAME, SMTP_AUTH_USER, SMTP_AUTH_PWD);

    transport.sendMessage(message,
            message.getRecipients(Message.RecipientType.TO));
    transport.close();
}

But when I try to call it from a servlet in the web application I get the following:

HTTP ERROR 500

Problem accessing /tokenAndSecret. Reason:

    javax.net.ssl.SSLSocketFactory is a restricted class. Please see the Google  App Engine developer's guide for more details.

Caused by:

java.lang.NoClassDefFoundError: javax.net.ssl.SSLSocketFactory is a restricted class. Please see the Google  App Engine developer's guide for more details.
        at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51)
        at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:279)
        at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:231)
        at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1900)
        at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:638)
        at javax.mail.Service.connect(Service.java:248)
        at javax.mail.Service.connect(Service.java:91)
        at com.sirma.itt.saas.api.mail.SSLMailSender.send(SSLMailSender.java:64)
        at com.sirma.itt.saas.app.servlets.TokenAndSecretServlet.doGet(TokenAndSecretServlet.java:71)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
        at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:35)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:60)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:97)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
        at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
        at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
        at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
        at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
        at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:78)
        at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
        at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:363)
        at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
        at org.mortbay.jetty.Server.handle(Server.java:326)
        at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
        at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
        at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
        at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
        at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
        at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
        at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

Any idea what causes this and how can be fixed?

Answer 1

App Engine doesn’t support opening sockets. Instead, use the Mail Api to send mail from App Engine.