During spring 2008 I was teaching the Java EE course in Shenkar college. It was delivered as part of Shenkar B.S.c. in software engineering. Unlike the Java EE courses I taught so far in Shenkar this time I chose to take Java ME out of the syllabus and teach EJB instead.
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.