code: public static int findLastOf (String container, String charSeq, int begin){        
  		//find the last occurrence of one of characters in charSeq from begin backward
          for (int i = begin; i < container.length() && i >= 0; --i){
              if (charSeq.contains("" + container.charAt(i)))
                  return i;
          }
          return -1;        
      }
docs: Find the last occurrence.
  
  @param container the string on which we search
  @param charSeq the string which we search for the occurrence
  @param begin the start position in container to search from
  @return the position where charSeq occurs for the last time in container (from right to left).