public static String stripCharsInBag(String s,String bag){
  int i;
  StringBuilder stringBuilder=new StringBuilder("");
  for (i=0; i < s.length(); i++) {
    char c=s.charAt(i);
    if (bag.indexOf(c) == -1)     stringBuilder.append(c);
  }
  return stringBuilder.toString();
}

public static String stripCharsInBag ( String s , String bag ) { int i ; StringBuilder stringBuilder = new StringBuilder ( "" ) ; for ( i = 0 ; i < s . length ( ) ; i ++ ) { char c = s . charAt ( i ) ; if ( bag . indexOf ( c ) == - 1 ) stringBuilder . append ( c ) ; } return stringBuilder . toString ( ) ; }
removes all characters which appear in string bag from string s .
