try{
    //  here I try to create a Message
    //  as well as invoke the send method
    //  from a class in JavaMail- (keep in 
    //  mind I've never gone through the 
    //  JavaMail API so this is simply an 
    //  educated guess of what the pseudo 
    //  would look like)
}catch(AServerException se){
    System.out.println("Connection failed - or send failed");
    //  Once again AServerException is a fictitions
    //  class that handles one form of an exception.
    se.printStackTrace();
}catch(SendFailedExcpetion fe){
    System.out.println("Send Failed");
    fe.printStackTrace();
}

Session.getInstance(Properties, Authenticator);
// see JavaMail API
[/null]
No clearly if you pass in null when it is expecting
a properly set Authenticatory object, it will
definitely be throwing those Security Exceptions.
 
Try setting up a proper javax.mail.Authenticator and
pass it in accordingly.  E.g:
 
[java]
my_session = Session.getInstance(yourProperty, new Authenticator(){
      //  override the abstract methods or simply
      //  pass this one in by creating a class extension
});

System.out.println("Creating Mail Session");
Session mailSession = Session.getInstance(props, new
        new MailAuthenticator());
System.out.println("created mail Session");
 
class MailAuthenticator extends Authenticator
{
   public PasswordAuthentication
         getPasswordAuthentication() {
       System.out.println("Password Authentication");
       return new PasswordAuthentication("myid", "mypwd");
   }
}
[/java