code: public static String getMimeType(InputStream is, String defaultValue) {
  	try {
  	    return getMimeType(IOUtil.toBytesMax(is, 1000), defaultValue);
  	}
  	catch (IOException e) {
  	    return defaultValue;
  	}
      }
docs: return the mime type of a file, dont check extension
  
  @param barr
  @param defaultValue
  @return mime type of the file