pre-selected value in combobox not working

I'm showing a collection of beans in a combobox. 
When creating the combobox, I want to preselect the previously saved selection. This bean (called "selectedBean" in the example below) is retrieved in a different hibernate-transaction than the bean-collection and therefore is not the same instance as the matching object in the collection. 
I implemented the equals-method for Type "MyBeanType" and expected this to work:

List<MyBeanType> beans = myService.findAll();
        myBeanContainer = new BeanItemContainer<MyBeanType>(MyBeanType.class);
        myBeanContainer.addAll(beans);
        view.setContainer(myBeanContainer); //view sets container and selected value on combobox
        view.setSelectedBean(selectedBean);

But strangely no value is selected!
But when I change my code to this, it works:

List<MyBeanType> beans = myService.findAll();
        for (MyBeanType beanInCollection : beans) {
            if (beanInCollection.equals(selectedBean))
                selectedBean = beanInCollection;
        }
        myBeanContainer = new BeanItemContainer<MyBeanType>(MyBeanType.class);
        myBeanContainer.addAll(beans);
        view.setContainer(myBeanContainer);
        view.setSelectedBean(selectedBean);

The value in the collection corresponding "selectedBean" is selected correctly. That means my equals-method is working. But somehow it is not used by vaadin to identify the selected value. Why is that? What am I missing?

Did you remember to override hashCode() as well?

Thank you Anna, that was my problem.

simple question...simple answer.