Cannot replace Arabic Apache POI characters in MS Word file

I need to dynamically modify Word files with values ​​from a database or enter by user. Values ​​and files are in Arabic.

The problem is that it does not work all the time. Each time I come across a new and different problem with Arabic characters.

The code I'm using is:

        FileInputStream in = new FileInputStream(path+"\\fiches\\"+fileName.trim()+".doc");
        POIFSFileSystem fs = new POIFSFileSystem(in);
        HWPFDocument doc = new HWPFDocument(fs);
        Range  r = doc.getRange();
         r.replaceText("<matricule>","  "+agent.getMatriculeAgent());
        r.replaceText("<cin>","  "+agent.getCin());
        r.replaceText("<الإسم الشخصي>", " "+agent.getPrenomAgentArabe());
        OutputStream out = response.getOutputStream();
        response.setContentType("application/rtf");
        response.setHeader("Content-Disposition","attachment; filename="+fileName);
        doc.write(out);
        out.flush();