org.hibernate.QueryException: could not resolve property with column name already defined
<p>This is the first time I use SpringMVC+Hibernate, so forgive me if I asked a noob question.</p>

<p>The relationship of database tables looks like this:
<a href="https://i.stack.imgur.com/Y2RcB.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Y2RcB.jpg" alt="Text in red color are my tables"></a></p>

<p>And what I want to implement is searching for <em>user_tasks</em> which belongs to some <em>user</em>. So in the implementation of UserRepository I wrote this:</p>

<pre><code>@Repository("userTaskRepo")
public class UserTaskRepoImpl extends AbstractDao&lt;Integer, UserTask&gt; implements UserTaskRepository {

    public List&lt;UserTask&gt; getByUserId(int userId, int startTaskId, int size) {
        List&lt;UserTask&gt; userTasks = getSession().createCriteria(UserTask.class)
                .add(Restrictions.eq("user_id", userId))
                .add(Restrictions.ge("task_id", startTaskId))
                .setMaxResults(size)
                .list();
        return userTasks;
    }
}
</code></pre>

<p>and the related <em>UserTask</em> class are defined as follows:</p>

<pre><code>@Entity
@Table(name = "usertask")
public class UserTask {
    //public enum TaskState {CLAIMED, FINISHED, EXPIRED};
    public static int TYPE_CLAIMED = 0;
    public static int TYPE_FINISHED = 1;
    public static int TYPE_EXPIRED = 2;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name = "user_id", nullable = false)
    private Integer userId;

    @Column(name = "task_id", nullable = false)
    private Integer taskId;

    @Column(name = "curr_usermicrotask_id")
    private Integer currUserMicrotaskId;

    @Column(name = "state", nullable = false)
    private Integer state;

    //...some getters and setters
}
</code></pre>

<p>Also, I have classes of <em>User</em> and <em>Task</em> defined.</p>

<p>However, error occurs when I tried to call the function in the UserTaskRepoImpl
exception</p>

<pre><code>org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.QueryException: could not resolve property: user_id of: edu.inlab.models.UserTask
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:979)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
</code></pre>

<p>Could anyone figure out why this happened?
Thanks in advance!</p>