Next create a frame (window) and display your file data in a TextArea on it.  You should read the data about your products from the file into an array of objects.  Then display (by appending) the data in a TextArea.

Include a button on the window that will display the file when it is clicked.  For this, you should create an inner class with an actionPerformed method.  This method will be performed when the button is clicked.

     class DisplayListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e)
          {
               roster.displayList ();
          } // actionPerformed
     } // DisplayListener

You must instantiate the button (get a new instance of the Button class) and then add a listener to the button.
     display = new Button ("Display Data");
     display.addActionListener (new DisplayListener ());

Hand in a disk and a printout of your program.