Java - File handling - String Manipulation - remove unnecessary space between words

// File Handling

// String manipulations

/*

Write a program that copies the content of one file to another by removing unnecessary space between words

*/

import java.io.*;

class Filespace

{

     public static void main(String as[]) throws IOException

     {

          FileReader fr = new FileReader("ipt2.txt");

          FileWriter fw = new FileWriter("opt2.txt");

          BufferedReader br = new BufferedReader(fr);

         

          while(true)

          {

              String str = br.readLine();

             

               if(str==null)

                   break;             

             

              String sa[] = str.split(" ");

             

              for(String s:sa)

              {  

                   s = s.trim();

                   if(s.length()!=0)

                        fw.write(s+" ");

              }

              fw.write("\n");

          }

          fr.close();

          fw.close();

     }

}