Java CharArrayWriter write to file

import java.io.CharArrayWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Main {
  public static void main(String args[]) throws IOException {
    String s = "test from demo2s.com";
    char buf[] = new char[s.length()];
    s.getChars(0, s.length(), buf, 0);/*from  w  ww  .j  a va2s  . c o  m*/
    
    CharArrayWriter f = new CharArrayWriter();    
    f.write(buf);
    System.out.println(f.toString());

    FileWriter f2 = new FileWriter("Main.txt");
    f.writeTo(f2);
    f2.close();
  }
}