Query query=session.createQuery(hql);报空值异常

package com.imooc.model;

import java.util.List;

import org.hibernate.Query;

import org.hibernate.Session;

import org.junit.Test;

import org.junit.jupiter.api.AfterEach;

import org.junit.jupiter.api.BeforeEach;

import com.imooc.entity.Seller;

import com.imooc.util.HibernateSessionFactory;

public class SellerTest {

private Session session=null;

@BeforeEach

void setUp() throws Exception {

session=HibernateSessionFactory.getSession();

}

@AfterEach

void tearDown() throws Exception {

session.close();

}

@Test

public void testSeller() {

String hql="from Seller";

Query query=session.createQuery(hql);

List<Seller> sellers=query.list();

for(Seller seller:sellers) {

System.out.println(seller);

}

}

}