Process many files concurrently

Question

My program removes footnotes from a file read in, where the footnotes have the form [...].
Currently it just reads in one file and prints the output to an output file.
But I want it to remove footnotes from about 40 files that I have.
How can I modify the program so that it reads in all of the files the user wants the footnotes removed from, and prints all of the resulting files to new files? (i.e.without having to process each file individually?
/** This program reads in a text file and removes [...] characters from it
  * even when there are punctuation characters between the brackets
  *@author
import java.io.*;
import java.util.*;
import java.util.regex.*;
public class Footnotes2
public static void main (String [] args)
try
    InputStream in;
   in = new FileInputStream(Input.readString("Input Filename:"));
        // Set up character stream
        BufferedReader r = new BufferedReader(new InputStreamReader(in, "8859_1"));
//open output stream
Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(Input.readString("outfilename:")), "8859_1"));
String line = null;
    while( (line = r.readLine() ) != null)
          String regexp = "(\\[[\\w\\s\\w\\.\\,\\'\\`\\!\\?\\(\\)\\;\\:]*\\])+";
          Pattern patt = Pattern.compile(regexp);
          String footnote = new String(line);
          String text = patt.matcher(footnote).replaceAll("");
out.write(text);
out.write("\n");
out.flush();
out.close();
catch(IOException e)
System.out.println("IOException caught");
System.out.println(e.getMessage());
}  

Answer 1

Step one) Make the "remove" bit a method that takes a file name for the file you wsih to edit.
Step two) Using the methods in java.io.File, create a list of all the files in a folder (or using the command line args, or read from standard in, up to you)
Step three) Call the method created earlier for each of the files returned above.
Now, your subject says "concurrently" which suggests threading, but the question body does not suggest that threading is required.