*** It is a bug. ***
Sun inconsistently returns Session when you're inside their Glassfish EE container, and a MailConfiguration if you're inside a non-compliant portion of their Glassfish EE container or a 3rd party container. Here's a work around:
// Outside the EJB container, MailSession lookups return a MailConfiguration rather
// than a mail Session like one would expect.
context = new InitialContext();
Object object = context.lookup("mail/MyMailSession");
Session session = null;
if (object instanceof MailConfiguration)
{
MailConfiguration configuration = (MailConfiguration) object;
session = Session.getInstance(configuration.getMailProperties());
}
else if (object instanceof Session)
{
session = (Session) object;
}
// Compose the e-mail message.
Message message = new MimeMessage(session);
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