question: private static String handleInvalidChars ( String str ) { String result = "" ; final String replaceAmpresand1 = "&" ; final String replaceAmpresand2 = "amp;" ; final String replaceAmpresand = replaceAmpresand1 + replaceAmpresand2 ; final int ampLength = replaceAmpresand2 . length ( ) ; StringTokenizer strTokinizer = new StringTokenizer ( str , String . valueOf ( replaceAmpresand1 ) , true ) ; while ( strTokinizer . hasMoreTokens ( ) ) { String token = strTokinizer . nextToken ( ) ; if ( token . startsWith ( replaceAmpresand2 ) ) { token = token . substring ( ampLength ) ; } else if ( token . equals ( replaceAmpresand1 ) ) { token = replaceAmpresand ; } result += token ; } return result ; }
target:  This method goes through passed string and replace each occurrence of '&' to '&amp;'