code: public static boolean isWebJar(File file) {
          Set<String> found = new LinkedHashSet<>();
          if (file.isFile() && file.getName().endsWith(".jar")) {
              JarFile jar = null;
              try {
                  jar = new JarFile(file);
  
                  // Fast return if the base structure is not there
                  if (jar.getEntry(WEBJAR_LOCATION) == null) {
                      return false;
                  }
  
                  Enumeration<JarEntry> entries = jar.entries();
                  while (entries.hasMoreElements()) {
                      JarEntry entry = entries.nextElement();
                      Matcher matcher = WEBJAR_REGEX.matcher(entry.getName());
                      if (matcher.matches()) {
                          found.add(matcher.group(1) + "-" + matcher.group(2));
                      }
                  }
              } catch (IOException e) {
                  LoggerFactory.getLogger(DependencyCopy.class).error("Cannot check if the file {} is a webjar, " +
                          "cannot open it", file.getName(), e);
                  return false;
              } finally {
                  final JarFile finalJar = jar;
                  IOUtils.closeQuietly(new Closeable() {
                      @Override
                      public void close() throws IOException {
                          if (finalJar != null) {
                              finalJar.close();
                          }
                      }
                  });
              }
  
              for (String lib : found) {
                  LoggerFactory.getLogger(DependencyCopy.class).info("Web Library found in {} : {}",
                          file.getName(), lib);
              }
  
              return !found.isEmpty();
          }
  
          return false;
      }
docs: Checks whether the given file is a WebJar or not (http://www.webjars.org/documentation).
  The check is based on the presence of {@literal META-INF/resources/webjars/} directory in the jar file.
  
  @param file the file.
  @return {@literal true} if it's a bundle, {@literal false} otherwise.