Data access layer in java web-app

It's time for a good old discussion. About a year ago, I designed a webapplication which manages at testsystem for a company. This means a lot of settings, equipment, readings, setups - you name it - is persisted. This also means, that when a user for example wants to load a table with all tests, I really don't want to load 1.5 million readings alongside from the database.

So of course, I used lazy loading. When a user then chose a test, and wanted to see the results, all the results was loaded from the database then. At the time, I used Eclipselink. That worked - as I understand because Eclipselink automatically opens a new session when trying to fetch something that is annotated with lazy fetchtype.

Now, a year older and smarter, I'm doing some refactoring. A big change was leaving Eclipselink for Hibernate ( Also good to learn new stuff ). Suddenly, I get the good old LazyInitializationException. And yes, I now see that my DAO-structure is not working.

/**
 * The Class DAO which all the other EntityDAOS extend
*/

public class DAO {

    /** The entitymanager. */
    private EntityManager entitymanager;


    /**
     * Gets the entitymanager
     *
     * @return the manager
     */
    public EntityManager getManager(){
        entitymanager = FactoryMaker.getFactory().createEntityManager();
        entitymanager.getTransaction( ).begin( );
        entitymanager.flush();
        entitymanager.clear();
        return entitymanager;

    }

    /**
     * Commit and clear the manager.
     */
    public void Close(){
        if(entitymanager.isOpen()){
            if(entitymanager.getTransaction().isActive()){
                entitymanager.getTransaction().commit();
                entitymanager.clear();
            }

            entitymanager.close();
        }
    }

    @Override
    protected void finalize() throws Throwable {
        super.finalize();
    }

}

As clearly seen in the save-example below, the session is closed immediatly.

public void SaveSomething(Something t){
    EntityManager manager = getManager();
    manager.merge(t);
    manager.flush();
    Close();
}

So this is clearly not a good solution. Now - in your oppinion - what is the best way of creating a Data Access Layer for a webapplication, where lazy loading is a requirement and data from the database is the base for the whole system?