public void setDebugEnabled(boolean debugEnabled) {
        this.debugEnabled = debugEnabled;
        JiveGlobals.setProperty("mail.debug", Boolean.toString(debugEnabled));
        session = null;
    }
Enables or disables SMTP transport layer debugging. Debug information is
written to {@code System.out} by the underlying JavaMail provider.

@param debugEnabled true if SMTP debugging should be enabled.
xmppserver/src/main/java/org/jivesoftware/util/EmailService.java