Java code for extracting email addresses from a text file using regular expression

import java.io.*;

import java.util.regex.*;

public class harness {

 /**

  * @param args

  */

 public static void main(String[] args) {

 // TODO Auto-generated method stub

        File aFile = new File(<bulk_content.txt>);

        Pattern regexp = Pattern.compile("");

        Matcher matcher = regexp.matcher("([a-zA-Z0-9\\+\\.\\_\\%\\-\\+]{1,256}\\@[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}(\\.[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25})+)");

        LineNumberReader lineReader = null;

        try {

         FileWriter fstream = new FileWriter("<emails.txt>");

         BufferedWriter out = new BufferedWriter(fstream);

         lineReader = new LineNumberReader(new FileReader(aFile));

               String line = null;

               while ((line = lineReader.readLine()) != null){

               matcher.reset(line);

               while (matcher.find()) {

                 out.write(matcher.group() + "\n");

               }

              }

        }

        catch (FileNotFoundException ex) {

         ex.printStackTrace();

        }

        catch (IOException ex){

         ex.printStackTrace();

        }

        finally {

         try {

          if (lineReader!= null) lineReader.close();

            }

            catch (IOException ex) {

             ex.printStackTrace();

            }

        }      

 }

}