code: private boolean copyRelease(Path src, Path dest, boolean isTop, boolean isForced) {
      try {
  
        if (!fs.exists(dest)) {
          if (!fs.mkdirs(dest)) {
            LOG.error("Unable to make dir " + dest.toString());
            return false;
          }
        } else {
          if (isTop && !isForced) {
            Path donePath = new Path(dest, RELEASE_TAG_FILE);
            if (fs.exists(donePath)) {
              LOG.info(donePath + " exists. There is no need to copy again");
              return true;
            }
          }
        }
        for (FileStatus fileStat: fs.listStatus(src)) {
          Path srcPath = fileStat.getPath();
          if (!fileStat.isDir()) {
            boolean copyFlag = true;
            if (release_pattern != null) {
              Matcher m = release_pattern.matcher(srcPath.toString());
              if (!m.find()) {
                copyFlag = false;
              }
            }
            if (copyFlag) {
              Path destPath = new Path(dest, srcPath.getName());
              fs.copyFromLocalFile(srcPath, destPath);
            }
          } else {
            Path destPath = new Path(dest, srcPath.getName());
            if (!copyRelease(srcPath, destPath, false, isForced)) {
              LOG.error("Unable to create link for " + srcPath.toString() +
                " as " + destPath.toString());
              return false;
            }
          }
        }
        if (isTop) {
          // create the tag file
          Path donePath = new Path(dest, RELEASE_TAG_FILE);
          FSDataOutputStream fos = fs.create(donePath);
          fos.close();
        }
      } catch (IOException ioe) {
        LOG.error("IOException when link dir ", ioe);
        return false;
      }
      return true;
    }
docs: For every jar files from the source, create a link in the dest