/**
   * Checks the dependencies of the jar file on installed extension.
   *
   * @param jarFile containing the attriutes declaring the dependencies
   */
  public static synchronized boolean checkExtensionsDependencies(JarFile jar) {
    if (providers == null) {
      // no need to bother, nobody is registered to install missing
      // extensions
      return true;
    }

    try {
      ExtensionDependency extDep = new ExtensionDependency();
      return extDep.checkExtensions(jar);
    } catch (ExtensionInstallationException e) {
      debug(e.getMessage());
    }
    return false;
  }
 /*
  * parse the standard extension dependencies
  */
 private void parseExtensionsDependencies() throws IOException {
   ExtensionDependency.checkExtensionsDependencies(jar);
 }