Method startTLS

app/src/main/java/com/sun/mail/iap/Protocol.java:463–470

Start TLS on the current connection. cmd is the command to issue to start TLS negotiation. If the command succeeds, we begin TLS negotiation. If the socket is already an SSLSocket this is a nop and the command is not issued. @param cmd the command to issue @exception IOException for I/

(String cmd)

     * @exception	ProtocolException	for protocol failures
     */
    public synchronized void startTLS(String cmd)
				throws IOException, ProtocolException {
	if (socket instanceof SSLSocket)
	    return;	// nothing to do
	simpleCommand(cmd, null);
	socket = SocketFetcher.startTLS(socket, host, props, prefix);
	initStreams();
    }

    /**
     * Start compression on the current connection.