aSmack - login

// Do nothing if the connection is null, or connection is not established, or // connection is authenticated if (connection == null || !connection.isConnected() || connection.isAuthenticated()) { return; } String username = "alice"; // username without '@' String password = "123456"; // this user's password try { connection.login(username, password); } catch (XMPPException e) { Log.e("login", "XMPPException: "+e.getMessage()); } catch (IllegalStateException e) { Log.e("login", "IllegalStateException: "+e.getMessage()); } catch (Exception e) { Log.e("login", "Exception: "+e.getMessage()); }