code: @GwtIncompatible("Unnecessary")
    public final void run() {
      int result;
      try {
        result = doRun();
      } catch (FlagUsageException e) {
        err.println(e.getMessage());
        result = -1;
      } catch (Throwable t) {
        t.printStackTrace(err);
        result = -2;
      }
  
      exitCodeReceiver.apply(result);
    }
docs: Runs the Compiler and calls System.exit() with the exit status of the compiler.