Error message

Exception in thread "main" java.lang.ClassCastException: com.itheima.dao.impl.UserDaoImpl cannot be cast to com.itheima.dao.UserDao
	at com.itheima.demo.UserDaoDemo.main(UserDaoDemo.java:10)
Copy the code

The error code is

UserDao userDao = (UserDao) app.getBean("userDao");
Copy the code

UserDaoImpl forgot to implement the interface UserDao

public class UserDaoImpl implements UserDao {
    public void save(a){
        System.out.println("save running...");
    }
Copy the code