Question

How can i write this code into a Thread or an AsyncTask ?

JSch jsch = new JSch();
    Session session = null;
        session = jsch.getSession("******", "*********",22);
        session.setConfig("StrictHostKeyChecking", "no");     
        session.setPassword("******");
        session.connect();
        Channel channel = session.openChannel("sftp");
        channel.connect();
        ChannelSftp sftpChannel = (ChannelSftp) channel;     
        sftpChannel.exit();
        session.disconnect();

Answer 1

To write it in a thread, just create a new thread object containing a Runnable process.

Thread connectionThread = new Thread(new Runnable() {
    public void run() {
        JSch jsch = new JSch();
        Session session = null;
        session = jsch.getSession("******", "*********",22);
        session.setConfig("StrictHostKeyChecking", "no");     
        session.setPassword("******");
        session.connect();
        Channel channel = session.openChannel("sftp");
        channel.connect();
        ChannelSftp sftpChannel = (ChannelSftp) channel;     
        sftpChannel.exit();
        session.disconnect();
    }
});

This can then be run at anytime with

connectionThread.start();

More information on Threads, ASyncTasks and other processes can be found here:
http://developer.android.com/guide/components/processes-and-threads.html