Question
Which of the following are true about Observer and Observable?
- A. Observer is an interface and Observable is a class?
- B. When an Observable object is updated it invokes the
update() method of its observers. - C. Observable objects must be GUI components.
- D. They are in the Collections API.
A and B.
Note
Observer and Observable are not part of the Collections API.
They do not have any relationship to GUI components.
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