GWT RPC mail error:javax.mail.NoSuchProviderException: Unable to locate provider for protocol: smtp

Hi,

I am trying to send html mail in GWT project through RPC call .
the RPC method is invoked successfully, but when the code gets to the
following line:

Transport transport = mailSession.getTransport("smtp");

I get
javax.mail.NoSuchProviderException: Unable to locate provider for
protocol: smtp

i have download javamail 1.4.5 and added the jars to the buildpath
(including smtp.jar ) but nothing helps.

could you please advice ?

* see below full code:
try{
final String from = "mymail@gmail.com";
final String password = "mypassword";
final String to = "maildestiny@gmail.com";
final String body = "<body> bla bla </body>";

String host = "smtp.gmail.com";
Properties props = System.getProperties();
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.host", host);
props.put("mail.smtp.user", from);
props.put("mail.smtp.password", password);
props.put("mail.smtp.port", "587");
props.put("mail.smtp.auth", "true");
Session mailSession = Session.getDefaultInstance(props,
null);
// mailSession.setDebug(true);
MimeMessage message = new MimeMessage(mailSession);
message.setSubject("bla bla blu");
message.setFrom(new InternetAddress(from));
message.setContent(body, "text/html");
InternetAddress toAddress = new InternetAddress(to);
message.addRecipient(Message.RecipientType.TO,
toAddress);
Transport transport = mailSession.getTransport("smtp");
transport.connect(host, from, password);
transport.sendMessage(message, message.getAllRecipients());
transport.close();
} catch (MessagingException e) {
e.printStackTrace();
}

Welcome to the Ranch.

Is the code executed on the client or server side?

its running on the server side

This is not really a GWT issue. I will move this topic to a more appropriate forum for you.
In the mean while check out http://www.coderanch.com/t/274207/java/java/Sending-Email-Java-mail-API

I read on the internet that in order to use java mail jar i should disable google app engine mail.
I did it by removing in from the libraries in the java build path tab (I'm using eclipse), and from the google menu : I removed the V from "use google app engine" checkbox.

but I still see in the log :
DEBUG: loading new provider protocol=gm, className=com.google.appengine.api.mail.stdimpl.GMTransport, vendor=null, version=null
Starting Jetty on port 8888

maybe this is the reason for the exception? how come it looks on appengine class if I removed it from classpath?

I found I still had the appengine jars in my war/WEB-INF/LIB.
I removed it and now I get following exception :
java.net.UnknownHostException: smtp.gmail.com