code: public static boolean isJCB(String cc) {
          String first4digs = cc.substring(0, 4);
  
          if ((cc.length() == 16) &&
              (first4digs.equals("3088") ||
                  first4digs.equals("3096") ||
                  first4digs.equals("3112") ||
                  first4digs.equals("3158") ||
                  first4digs.equals("3337") ||
                  first4digs.equals("3528")))
              return isCreditCard(cc);
          return false;
      }
docs: Checks to see if the cc number is a valid JCB number
  @param     cc - a string representing a credit card number; Sample number: 3088000000000009(16 digits)
  @return  true, if the credit card number is a valid JCB card number, false otherwise