Spring Hibernate:現在のスレッドでセッションが見つかりません

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <bean id="dataSource" 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/test"/>
        <property name="username" value="root"/>
        <property name="password" value="password"/>
    </bean>

    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="mappingResources">
            <list>
                <value>orm/Users.hbm.xml</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <value>
                hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
            </value>
        </property>
    </bean>

    <bean id="userDao" class="com.mkyong.users.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

    <bean id="userService" class="com.mkyong.users.service.UserServiceImpl">
        <property name="userDao" ref="userDao"/>
    </bean>

    <bean id="txManager"
        class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>

    <tx:advice id="txAdvice" transaction-manager="txManager">
        <tx:attributes>
            <tx:method name="find** " read-only="true"/>
            <tx:method name="** "/>
        </tx:attributes>
    </tx:advice>

    <aop:config>
        <aop:pointcut id="userServicePointCut"
            expression="execution(**  com.mkyong.users.service.** Service.** (..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="userServicePointCut"/>
    </aop:config>

</beans>

package com.mkyong.users.service;
//...
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;

public class UserServiceImpl implements UserService {

  private UserDao userDao;

  private TransactionTemplate transactionTemplate;

  public void setTransactionManager(PlatformTransactionManager transactionManager) {
    this.transactionTemplate = new TransactionTemplate(transactionManager);
  }

  @Override
  public UserDetails findByUsername(final String username) {

   //Programmatic transaction management
    return transactionTemplate.execute(new TransactionCallback<UserDetails>() {

      public UserDetails doInTransaction(TransactionStatus status) {

                UserDetails user = userDao.findByUserName(username);
               //etc etc

      }

    });

  }