docs: public void putClass(String key, Class<?> clazz) {
  		checkNotNull(key);
  		checkNotNull(clazz);
  		final String error = InstantiationUtil.checkForInstantiationError(clazz);
  		if (error != null) {
  			throw new ValidationException("Class '" + clazz.getName() + "' is not supported: " + error);
  		}
  		put(key, clazz.getName());
  	}