How to fix this issue : Method does not override or implement a method from a supertype @Override

Question

Hello folks I don't know where is the issue in the code can you help me please. ERROR 1: UsersDao is not abstract and does not override abstract method delete in DaoList. Error 2: Method does not override or implement a method from a supertype @Override

UsersDao.java :

public class Users extends db implements DaoList<Users>{
private static UsersDao userDao;
private UsersDao(){
}
public static UsersDao getInstance(){
    if(userDao == null){
        userDao = new UsersDao();
    }
    return userDao;
}
@Override
public List<UsersVo> loadAll(Users u) throws Exception {
    throw new UnsupportedOperationException("Not supported yet."); 
}
@Override
public int insert(Users u) throws Exception {
    Connection con = null;
    PreparedStatement ps = null;
    int count = 0;
    try{
    con = getConnection();
    String sql = "INSERT INTO USERS(USERNAME,PASSWORD,EMAIL) VALUES(?,?,?)";
    ps = con.prepareStatement(sql);
    ps.setString(1, u.getUserName());
    ps.setString(2, u.getPassWord());
    ps.setString(3, u.getEmail());
    count = ps.executeUpdate();
    }catch(Exception ex){
         
    }finally{
            ps.close();
            closeConnection(con);
    }
    return count;

}

@Override
public int update(Users u) throws Exception {
    throw new UnsupportedOperationException("Not supported yet."); 
}


@Override
public int delete(Users u) throws Exception {
    throw new UnsupportedOperationException("Not supported yet."); 
}

@Override
public PatientsVo getData(Users u) throws Exception {
    throw new UnsupportedOperationException("Not supported yet.");  
} } 

Answer 1

The error is telling you the exact problem - your code is attempting to @Override a method that does not exist in its super-class or implemented interfaces.

The UsersDao implementation class has:

@Override
public int insert(UsersVo uv) throws Exception {
}

whereas the DaoList interface you are implementing has:

public int insert() throws Exception;

The method signatures are different (namely the UserVo parameter), the interface should be:

public int insert(UsersVo uv) throws Exception;

(Ditto for the other methods)