Example:

 

Let's consider container classes which are typically used to hold references to objects of a given class. In a banking application, a specific type of container class, say AccountCollection, could be used to hold the list of identifiers to each account object. To generate a collection class that is capable of holding or managing only identifiers of checking account objects, the class name CheckingAccount is specified as a parameter when the collection class is created.

 

Suppose AccountCollection is a parameterized class whose definition is given elsewhere. Part of its class definition is as follows:

 

 

In another source unit, the following would create a class which is a collection of checking accounts and an object reference for this new kind of class.