code: protected Method getParse(Class cls) throws Exception {
      Method meth = methodCache.get(cls);
      if (null == meth) {
        meth = cls.getMethod("parseFrom", new Class[]{ byte[].class });
        methodCache.put(cls, meth);
      }
      return meth;
    }
docs: This is slow, so we should cache to avoid killing perf:
  See: http://www.jguru.com/faq/view.jsp?EID=246569