code: public static ClassLoadInfo classLoadManager() {
          ClassLoadingMXBean classLoadingMXBean = ManagementFactory.getClassLoadingMXBean();
          int nowLoadedClassCount = classLoadingMXBean.getLoadedClassCount();
          long totalLoadedClassCount = classLoadingMXBean.getTotalLoadedClassCount();
          long unloadedClassCount = classLoadingMXBean.getUnloadedClassCount();
          return new ClassLoadInfo(nowLoadedClassCount, totalLoadedClassCount, unloadedClassCount);
      }
docs: 获取class加载信息
  
  @return class加载信息