I want to open text file which is located on unix system and i want to display text content on swing UI.
when i am tryign to open getting java.io.FileNotFoundException: exception
Accessing a file has nothing to do with Swing. In order for a program to use a file it must have access to it - via FTP, HTTP, shared directory, WebDAV, or some other way. Start by finding out which way is feasible in your case.
Ulf is quite right. You should use a command‑line application to access a class which can open the file. When you can call getFileContents() on an object of that class and have the text appear on screen, then it will be easy to write a GUI on top which uses the same getFileContents() methid