code: public Class<?> getClassByName(String name) throws ClassNotFoundException {
          Map<String, Class<?>> map = CACHE_CLASSES.get(classLoader);
          if (map == null) {
              Map<String, Class<?>> newMap = new ConcurrentHashMap<>();
              map = CACHE_CLASSES.putIfAbsent(classLoader, newMap);
              if (map == null) {
                  map = newMap;
              }
          }
  
          Class clazz = map.get(name);
          if (clazz == null) {
              clazz = Class.forName(name, true, classLoader);
              if (clazz != null) {
                  map.put(name, clazz);
              }
          }
  
          return clazz;
      }
docs: Load a class by name.
  
  @param name the class name.
  @return the class object.
  @throws ClassNotFoundException if the class is not found.