Java interview questions part 8
Java interview questions part 8
Take as many assements as you can to improve your validate your skill rating
Total Questions: 20
1. What is the use of Observable class?
Correct Answer is : It is used to create classes that other part of the program can observe
2. Which of these methods is used to notify observer the change in observed object?
Correct Answer is : update()
3. Which of these methods calls update() method?
Correct Answer is : notifyObserver()
4. Which of these methods is called when observed object has changed?
Correct Answer is : all of the mentioned
5. Which of these classes can schedule task for execution in future?
Correct Answer is : Timer
6. Which of these interfaces is implemented by TimerTask class?
Correct Answer is : Runnable
7. Which of these package provides the ability to read and write in Zip format?
Correct Answer is : java.util.zip
8. Random is a final class?
Correct Answer is : FALSE
9. How many bits are used for generating random numbers?
Correct Answer is : 48
10. Math.random() guarantees uniqueness?
Correct Answer is : FALSE
11. Which class is used to generate random number?
Correct Answer is : java.util.Random
12. Which method is used to generate boolean random values in java?
Correct Answer is : nextBoolean()
13. What is the return type of Math.random() method?
Correct Answer is : Double
14. What is the range of numbers returned by Math.random() method?
Correct Answer is : 0.0 to 1.0
15. What would be the output of following code snippet? int a = random.nextInt(15) + 1;
Correct Answer is : Random number between 1 to 15, including 1 and 15
16. What would be the output of following code snippet? int a = random.nextInt(7) + 4;
Correct Answer is : Random number between 4 to 10, including 4 and 10
17. What is the signature of Math.random() method?
Correct Answer is : public static double random()
18. Which of these packages contains all the event handling interfaces?
Correct Answer is : java.awt.event
19. Which of these interfaces handles the event when a component is added to a container?
Correct Answer is : ContainerListener
20. Which of these interfaces define a method actionPerformed()?
Correct Answer is : ActionListener
