How to test if file is empty???

Question

I have written a program that reads from a text file.
How do i check that the file is empty,stop reading and display
an error message?
Here is the code i have.
try
      { FileReader in = new FileReader(fileName);
        BufferedReader reading= new BufferedReader(in);
        while (reading.ready())
        { StringTokenizer st = new StringTokenizer(reading.readLine());
          try
          { int k = Integer.parseInt(st.nextToken());
            /*I've tried this way but keep getting error
            if(k==null)
            { JOptionPane.showMessageDialog(null,
                            fileName+" is empty","Empty File",
                            JOptionPane.ERROR_MESSAGE );
              return;
            if(k>100)
               return;
            else
             Content[k].setText(st.nextToken());
          catch ( NumberFormatException nfe )
          { JOptionPane.showMessageDialog(null,
                            "All the addresses in file "+fileName+
                            " Must be integers","Invalid Address Format",
                            JOptionPane.ERROR_MESSAGE );
            return;
        for(int i=0;i<Content.length;i++)
        { Content.setEditable(false);
in.close();
catch ( IOException e )
{ JOptionPane.showMessageDialog( null,
"Error Opening File", "Error",
JOptionPane.ERROR_MESSAGE );

Answer 1

simply call File.length() on the file which returns a long with the number of bytes in the file...if 0, it's empty. Of course, if there are control codes (like \n or \t and nothing else in it) it won't be 0 bytes long but you would probably consider that empty too...so you must code accordingly.