code: protected Manifest getJarManifest(String assetId) throws IOException {
          File zipFile = new File(_root, assetId);
          ZipFile zip = DirectoryUtils.createZipFile(zipFile);
  
          String mfName = "meta-inf/manifest.mf";
          Manifest manifest = new Manifest();
          FileInputStream fis = DirectoryUtils.createFileInputStream(zipFile);
          ZipInputStream zis = new ZipInputStream(fis);
          try {
              ZipEntry ze = zis.getNextEntry();
              while (ze != null) {
                  if (ze.isDirectory()) {
                      // Do nothing with pure directory entries
                  } else {
                      String fileName = ze.getName();
                      if (fileName.equalsIgnoreCase(mfName)) {
                          InputStream is = zip.getInputStream(ze);
                          manifest.read(is);
                      }
                  }
                  ze = zis.getNextEntry();
              }
          } finally {
              zis.closeEntry();
              zis.close();
              zip.close();
          }
  
          return manifest;
      }
docs: {@inheritDoc}
  
  @throws IOException