docs: public static void main(String[] args) throws Exception {
          initCache();
          List<String> allClassnames = getAllClassNames();
          PrintStream out = System.out;
          if (args.length > 0)
              out = new PrintStream(new File(args[0]));
          Collections.sort(allClassnames);
          for (String clsname: allClassnames)
              out.println(clsname);
          out.flush();
          if (args.length > 0)
              out.close();
      }