Hibernate doesn't update record in MySQL database

I am using PrimeFaces 3.5, JSF 2.2, Hibernate 4.1, Spring 3.2.3, MySQL in my application. Function updateUser() is supposed to update record in the database for the selected user from the PrimeFaces dataTable component(values are correct) but for some unknown reason it doesn't. I have a class named AbstractDAO which implements CRUD operations via generics. Insertion, selection and deleting works perfectly, but update fails without showing any errors at all. Any clues what can be wrong in my code?

applicationContext.xml:

    <?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:sec="http://www.springframework.org/schema/security"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd">


    <!--            GLOABL SETTINGS             -->


    <context:component-scan base-package="com.infostroy.adminportal"/>
    <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true"/>


    <!--        DATA SOURCE AND PERSISTENCE SETTINGS       -->


    <bean id="propertiesPlaceholderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:db.properties</value>
            </list>
        </property>
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dmDataSource"/>
        <property name="packagesToScan" value="com.infostroy.adminportal"/>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">${db.dialect}</prop>
                <prop key="hibernate.show_sql">${db.show_sql}</prop>
                <prop key="hibernate.hbm2ddl.auto">${db.hbm2ddl_auto}</prop>
                <prop key="connection.pool_size">${db.pool_size}</prop>
                <prop key="current_session_context_class">${db.current_session_context_class}</prop>
                <prop key="org.hibernate.FlushMode">${db.flush_mode}</prop>
            </props>
        </property>
    </bean>


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


    <bean id="dmDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${db.driver}" />
        <property name="url" value="${db.url}" />
        <property name="username" value="${db.username}" />
        <property name="password" value="${db.password}" />
        <property name="maxWait" value="5000" />
        <property name="initialSize" value="2" />
        <property name="maxActive" value="100"/>
        <property name="maxIdle" value="50"/>
        <property name="minIdle" value="0"/>
    </bean>

</beans>

db.properties:

db.username=root
db.password=root
db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost/adminportal
db.pool_size=0
db.dialect=org.hibernate.dialect.MySQLDialect
db.hbm2ddl_auto=validate
db.show_sql=true
db.current_session_context_class=thread
db.flush_mode=COMMIT

AbstractDAO:

public abstract class AbstractDAO<T extends Serializable> implements Serializable {

@Autowired
protected SessionFactory sessionFactory;
protected T object;
protected Class clazz;

public AbstractDAO(Class clazz) {
    this.clazz = clazz;
}

//Executes before being removed from container
@PreDestroy
protected void destroy() {
    sessionFactory.getCurrentSession().close();
}

public Session getHiberSession() {
    return sessionFactory.openSession();
}

@Transactional
protected T getByID(int id) {
    String queryString = "from " + clazz.getSimpleName() + " where id = :id";
    Query query = getHiberSession().createQuery(queryString);
    query.setInteger("id", id);
    object = (T) query.uniqueResult();
    return object;
}

@Transactional
protected int deleteByID(int id) {
    String queryString = "delete " + clazz.getSimpleName() + " where id = :id";
    Query query = getHiberSession().createQuery(queryString);
    query.setInteger("id", id);
    return query.executeUpdate();
}

@Transactional
protected boolean insert(T object) {
    try {
        getHiberSession().save(object);
        return true;
    } catch (HibernateException ex) {
        return false;
    }
}

@Transactional
protected boolean update(T object) {
    try {
        getHiberSession().saveOrUpdate(object);
        return true;
    } catch (HibernateException ex) {
        return false;
    }
}

@Transactional
protected List getAllRecords() {
    String queryString = "from " + clazz.getSimpleName();
    Query query = getHiberSession().createQuery(queryString);
    return query.list();
}

}

UserDAO.java:

@Repository
public class UserDAO extends AbstractDAO<User> {

public UserDAO() {
    super(User.class);
}

public User getUserById(int id) {
    return super.getByID(id);
}

public int deleteUserById(int id) {
    return super.deleteByID(id);
}

public boolean insertUser(User user) {
    return super.insert(user);
}

public boolean updateUser(User user) {
    return super.update(user);
}

public List<User> getAllUsers() {
    return super.getAllRecords();
}
}

If you need any additional info or code - just tell me. Every answer is highly appreciated and responded immidiately.

Thank you.