Auto-generating a form based on a bean - Vaadin 6 style Form

In Vaadin 6 it is easy to get a completely auto generated form based on a bean instance by creating a BeanItem and passing that to a Form. Using FieldGroup this requires a few extra lines as FieldGroup never adds fields automatically to any layout but instead gives that control to the developer.

Given a bean such as this Person:

public class Person {
  private String firstName,lastName;
  private int age;
  // + setters and getters

You can auto create a form using FieldGroup as follows:

public class AutoGeneratedFormUI extends UI {
  public void init(VaadinRequest request) {
    VerticalLayout layout = new VerticalLayout();

    FieldGroup fieldGroup = new BeanFieldGroup<Person>(Person.class);

    // We need an item data source before we create the fields to be able to
    // find the properties, otherwise we have to specify them by hand
    fieldGroup.setItemDataSource(new BeanItem<Person>(new Person("John", "Doe", 34)));

    // Loop through the properties, build fields for them and add the fields
    // to this UI
    for (Object propertyId : fieldGroup.getUnboundPropertyIds()) {