http://teachersdoor.com/java112/unit1/Lab-1-6.html

LabSix.java

package java112.labs1;

import java.io.*;

public class LabSix {
  public static void main(String[] arguments) {
    if (arguments.length != 2) {
      System.out.println("Please enter two arguments on the command line, an input file name and an output file name");
    } else {
      LabSix lab = new LabSix();
      lab.run(arguments[0], arguments[1]);
    }
  }

  public void run(String inputFilePath, String outputFilePath) {
    BufferedReader in = null;
    PrintWriter out = null;

    try {

      // this requires catching FileNotFoundException
      in = new BufferedReader(new FileReader(inputFilePath));
      // this requires catching IOException
      out = new PrintWriter(new BufferedWriter(new FileWriter(outputFilePath)));

      mirrorFile(in, out);

    } catch (FileNotFoundException fileNotFoundException) {
      fileNotFoundException.printStackTrace();
    } catch (IOException ioException) {
      ioException.printStackTrace();
    } finally {

      if (in != null) {
        try {
          // this requires catching IOException
          in.close();
        } catch (IOException ioException) {
          ioException.printStackTrace();
        }
      }
      
      if (out != null) {
        out.close();
      }

    }
  }

  public void mirrorFile(BufferedReader in, PrintWriter out) {
    try {
      while (in.ready()) {
        out.println(in.readLine());
      }
    } catch (IOException ioException) {
      ioException.printStackTrace();
    }
  }
}