code: public static Provider getSunProvider() {
          try {
              Class<?> clazz = Class.forName(jarVerificationProviders[0]);
              return (Provider)clazz.newInstance();
          } catch (Exception e) {
              try {
                  Class<?> clazz = Class.forName(BACKUP_PROVIDER_CLASSNAME);
                  return (Provider)clazz.newInstance();
              } catch (Exception ee) {
                  throw new RuntimeException("Sun provider not found", e);
              }
          }
      }
docs: sun.security.util.ManifestEntryVerifier and java.security.SecureRandom.