code: public static boolean isPublic(Class<?> clazz) {
  		if (null == clazz) {
  			throw new NullPointerException("Class to provided is null.");
  		}
  		return Modifier.isPublic(clazz.getModifiers());
  	}
docs: 指定类是否为Public
  
  @param clazz 类
  @return 是否为public