Vibha:
I don't know of a standard
Java Class that would do this. What I would suggest is to build a class that can hold the data from your input file as a data structure of some type. Then build a new class that extends JPanel. You would overwrite the paint method of that class to paint (using 2D Graphics) your graph based on the data structure that is passed to it. Then display that new class in the ContentPane of a JFrame (or wherever you need to put it).
It's going to be a lot of "do it by hand" work to get it up and running though. Good luck.