code: public synchronized URL addPath(Path path, Path remoteFile) throws IOException, MalformedURLException {
  		if (paths.containsKey(remoteFile)) {
  			throw new IllegalArgumentException("duplicate path registered");
  		}
  		if (remoteFile.isAbsolute()) {
  			throw new IllegalArgumentException("not expecting an absolute path");
  		}
  		URL fileURL = new URL(baseURL, remoteFile.toString());
  		router.addAny(fileURL.getPath(), new VirtualFileServerHandler(path));
  
  		paths.put(remoteFile, fileURL);
  
  		return fileURL;
  	}
docs: Adds a path to the artifact server.
  @param path the qualified FS path to serve (local, hdfs, etc).
  @param remoteFile the remote path with which to locate the file.
  @return the fully-qualified remote path to the file.
  @throws MalformedURLException if the remote path is invalid.