Java: addSlashes() ?

/* Replace all instances of a String in a String.
 *   @param  s  String to alter.
 *   @param  f  String to look for.
 *   @param  r  String to replace it with, or null to just remove it.
 */  

public String replace( String s, String f, String r )
{
   if (s == null)  return s;
   if (f == null)  return s;
   if (r == null)  r = "";

   int index01 = s.indexOf( f );
   while (index01 != -1)
   {
      s = s.substring(0,index01) + r + s.substring(index01+f.length());
      index01 += r.length();
      index01 = s.indexOf( f, index01 );
   }
   return s;
}