cant connect after disconnected from ftp server

[naved momin]

i have develop an ftp app , but there is one problem
after being idle for some minutes the ftp server disconnects the client ...fine
but that ftp app has a jtree which fires treeselectionlistener 's value changed method in that method i have done something which is below

 if(ftp.isConnected() == true){}
                else
                {
                    try {
                        try {
                            ftp.connect(hostname);
                        } catch (IllegalStateException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        } catch (FTPIllegalReplyException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        } catch (FTPException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        }
                    } catch (SocketException ex) {
                        Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                    } catch (IOException ex) {
                        Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                    }

                    DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();


                    try {
                        try {
                            ftp.login(username , pass);
                        } catch (IllegalStateException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        } catch (FTPIllegalReplyException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        } catch (FTPException ex) {
                            Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                        }
                    } catch (IOException ex) {
                        Logger.getLogger(JTreeWithFTP.class.getName()).log(Level.SEVERE, null, ex);
                    }

so when the server disconnects my app , and when i m selecting any tree , because of my above few statements my app should reconnect with the server , right ?
but it is throwing an exception , saying connection has been aborted
or something like software caused connection abort

what i want is whenever ftp server disconnects my app
my app should able to reconnect to the server without even restarting my app
can i do this , offcourse yes , but how ??