I am not sure what you are talking about here, but it is nothing seam specific to create an array or list.
I guess you can create an array like this, however I discourage you from using Arrays and using List instead.
@In(create=true) private CalendarDataModelItem calendarDataModelItemImpl;
I agree with Shervin, it´s better for you to use Java 5 collections.
For instance, if ArrayList suits you:
@In(create=true) private ArrayList<CalendarDataModelItem> list = new ArrayList<CalendarDataModelItem>();
The only time I use arrays in Seam apps is when I have to.
List<Object> list = entityManager.createQuery("select c, o from Customer c, Order o where o.customer.customerId = c.customerId and o.orderId = :orderId") .setParameter("customerId", customerId) .setParameter("orderId", orderId) .getResultList();
When there is more than one entity in the select clause, the JPA provider returns a Object.
Otherwise, try to use the following pattern:
List<foo> list = new ArrayList<foo>();
Same thing applies for Sets:
Set<foo> set = new HashSet<foo>();
interface on the left side, concrete implementation on the right side to support polymorphism (e.g. you can swap in a LinkedList for the ArrayList later if required).