code: public static boolean isZip(String fileName) {
  		if (fileName == null) {
  			return false;
  		}
  
  		String tl = fileName.toLowerCase();
  		for (String element : ZIP_EXTENSIONS) {
  			if (tl.endsWith(element)) {
  				return true;
  			}
  		}
  		return false;
  	}
docs: Determines if the file has an extension known to be a ZIP file,
  currently this includes .zip, .jar, .war, .ear, .aar
  
  @param fileName The name of the file to check.
  @return True if the filename is of an extension that is a known zip file, false otherwise.