Removed the possibility using a class StringBuilder.
   boolean isMarkupStart = line.startsWith("\n***");
   if (isMarkupStart) {
   isStart = line.contains(START_TAG);
   isEnd = line.contains(END_TAG);
   inTag = isStart || isEnd;
   }
   if(inTag){
   tagForMatch.append(line);
   }else if (isInValidText) {
   super.insertString(bypass, offset, line, attr);
   }
   //The stringbuffer is to be sure *** is not broken into many lines
   if (inTag && tagForMatch.toString().endsWith("***")) {
   isInValidText = isStart && !isEnd;
   inTag = false;
   tagForMatch.setLength(0);
   }