Get the file extension from byte array

Below is the code snippet to get the file extension

public static Map<String, String> getImageType(byte[] imageContent) throws Exception {        Map<String, String> result = new HashMap<String, String>();        TikaConfig config = TikaConfig.getDefaultConfig();        MediaType mediaType = config.getMimeRepository().detect(new ByteArrayInputStream(imageContent), new Metadata());        MimeType mimeType = config.getMimeRepository().forName(mediaType.toString())        result.put("extn", mimeType.getExtension().replaceFirst(".", ""));        return result;    }

tika-core dependency used version 1.13

Above code is working fine for all the document having extension .pdf, .jpg, .csv, .txt, .bin, .jpeg and return expected extension Ex {extn=.pdf}, But it is not working when the file extension is .doc and .docx and return blank {extn=}

Expecting to get the .doc and .docx file extension ex:{extn=.doc}