Java Questions & Answers – Observable & Timer Class

This section of our 1000+ Java MCQs focuses on Observable & Timer class of Java Programming Language.

1. What is the use of Observable class?
a) It is used to create global subclasses
b) It is used to create classes that other part of the program can observe
c) It is used to create classes that can be accessed by other parts of program
d) It is used to create methods that can be accessed by other parts of program
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2. Which of these methods is used to notify observer the change in observed object?
a) update()
b) notify()
c) check()
d) observed()
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3. Which of these methods calls update() method?
a) notify()
b) observeObject()
c) updateObserver()
d) notifyObserver()
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4. Which of these methods is called when observed object has changed?
a) setChanged()
b) update()
c) notifyObserver()
d) all of the mentioned
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5. Which of these classes can schedule task for execution in future?
a) Thread
b) Timer
c) System
d) Observer
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6. Which of these interfaces is implemented by TimerTask class?
a) Runnable
b) Thread
c) Observer
d) ThreadCount
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7. Which of these package provides the ability to read and write in Zip format?
a) java.lang
b) java.io
c) java.util.zip
d) java.util.zar
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