Sample output

gistfile1.bat

C:\Users\oreyes\code\java\demo>dir
 El volumen de la unidad C es 
 El número de serie del volumen es:

 Directorio de C:\Users\oreyes\code\java\demo

04/07/2011  03:16 p.m.    <DIR>          .
04/07/2011  03:16 p.m.    <DIR>          ..
               0 archivos              0 bytes

C:\Users\oreyes\code\java\demo>more > Rt.java
import java.io.*;
class Rt {
  public static void main(String args[]) throws Exception {
          Runtime RT = Runtime.getRuntime();
          String  command =  "javap java.lang.String" ;
          File file = new File("write.txt");
          Writer output = new BufferedWriter(new FileWriter(file));
          BufferedReader br = new BufferedReader(new InputStreamReader(RT.exec(command).getInputStream()));
          String temp = br.readLine();
          while( temp != null ) { //!temp.equals(null)) {
              output.write(temp);
              temp = br.readLine();
          }
          output.close();
          //RT.exec("exit");
  }
}

C:\Users\oreyes\code\java\demo>javac Rt.java

C:\Users\oreyes\code\java\demo>java Rt

C:\Users\oreyes\code\java\demo>dir
 El volumen de la unidad C es 
 El número de serie del volumen es: 

 Directorio de C:\Users\oreyes\code\java\demo

04/07/2011  03:16 p.m.    <DIR>          .
04/07/2011  03:16 p.m.    <DIR>          ..
04/07/2011  03:16 p.m.             1,183 Rt.class
04/07/2011  03:16 p.m.               672 Rt.java
04/07/2011  03:16 p.m.             4,580 write.txt
               3 archivos          6,435 bytes