I am new to Hibernate/JPA. This is probably a very simple question. I have got class
@Entity
class University {

List<Department> departments = new ArrayList<Department>();

public List<Department> getDepartments() {
return departments;
}

}
Just wondering everytime when i make call to University.getDepartments(), Will Hibernate every time makes a Database call or picks from session?

Only once, assuming you invoke the method twice on the same physical object instance.

..assuming normal conditions, of course. You can of course write a query or map your object so no extra db call is needed, or retrieve your University object within different Hibernate Session/EntityManages instances causing several db calls etc.

/Jens

If you call just the getter of a collection, nothing will happen until you access the collection (e.g. size() or get()). Then hibernate will query the association unless it is not already initialized (e.g. you have eagerly selected it via your mapping or HQL).

Many Thanks for replying...

I basically need to print number of Departments in University

so when i am saving new Department i got two ways ,

1. After saving i can get University.getDepartment.size().
Is above a better approach or

2. int number;

save() {

session.save(department)
number++;
}

and print number.
Its a high volume website where i am implementing this.
Please suggest which approach is better

Where is your save-method implemented?

You should implement this functionality using a named query: