HibernateException: Could not obtain transaction-synchronized Session for current thread 3 - spring

Question

I am getting error:
org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread
If I add the below snippet in DataSourceContext.xml, I don't get any error and the application works as expected.
<bean id="userDAO" class="com.my.portal.user.UserDAOImpl">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
I would like my scan packages and register beans without above snippet in DataSourceContext.xml.
How can I achieve this?
Here are my complete code:
Web.xml
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/*.xml</param-value>
</context-param>
<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- Processes application requests -->
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>WEB-INF/spring/servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>appServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
DataSourceContext.xml
<!-- Data Source Setup -->
<bean id="myDS" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
<property name="username" value="root"/>
<property name="password" value=""/>
<property name="maxIdle" value="5"/>
<property name="maxActive" value="10"/>
</bean>
<!-- Hibernate Sessionfactory Bean Definition -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="myDS"/>
<property name="annotatedClasses">
<list>
<value>com.my.portal.user.User</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>
<!-- Hibernate Transaction Setup -->
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
User.java
#Entity
#Table(name="USER")
public class User {
#Id
#Column(name="UserId")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private int UserId;
private String FirstName;
private String LastName;
public int getUserId() {
return UserId;
}
public void setUserId(int userId) {
UserId = userId;
}
public String getFirstName() {
return FirstName;
}
public void setFirstName(String firstName) {
FirstName = firstName;
}
public String getLastName() {
return LastName;
}
public void setLastName(String lastName) {
LastName = lastName;
}
#Override
public String toString(){
return "UserId="+UserId+", FirstName="+FirstName+", LastName="+LastName;
}
}
UserController.java
#Controller
public class UserController {
private static final Logger logger = LoggerFactory.getLogger(UserController.class);
private UserService userService;
#Autowired
public UserController(UserService userService){
this.userService = userService;
}
#RequestMapping(value = "/user", method = RequestMethod.GET)
public String user(Locale locale, Model model){
model.addAttribute("getUser",userService.getUser());
return "user";
}
UserDAO.java
#Repository
public interface UserDAO {
public List<User> getUser();
}
UserDAOImpl.java
#Repository
#Transactional
public class UserDAOImpl implements UserDAO {
private static final Logger logger = LoggerFactory.getLogger(UserDAOImpl.class);
private SessionFactory sessionFactory;
#Autowired
public void setSessionFactory(SessionFactory sessionFactory){
this.sessionFactory = sessionFactory;
}
private Session currentSession() {
return sessionFactory.getCurrentSession();
}
#SuppressWarnings("unchecked")
#Override
public List<User> getUser() {
List<User> userList = currentSession().createQuery("from User").list();
return userList;
}
}
userService.java
#Service
public interface UserService {
public String getMessage();
}
UserServiceImpl.java
#Service
public class UserServiceImpl implements UserService {
private UserDAO userDAO;
#Autowired
public void setUserDAO(UserDAO userDAO) {
this.userDAO = userDAO;
}
public String getMessage(){
return "User Registration Page";
}
#SuppressWarnings("unchecked")
#Override
public List<User> getUser(){
logger.info("getUser()");
return this.userDAO.getUser();
}
}