Practice Happens-before Relationship (20.3) - Java Memory Model and Thread Safety

Practice: Happens-Before Relationship

Lesson 20.3Java Memory Model and Thread Safety

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8 questions

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4 cards from this section. Quick, good the night before a test.
Exercise
6 questions · about 4 min · pass mark 70%. Hints available.
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Quiz
2 questions · about 1 min · pass mark 70%. Hints available.
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6 sample questions

Question 1.
What does the happens-before relationship ensure?
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Think about how threads share data.
Question 2.
What does a volatile variable guarantee?
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Remember how variables can be read and written among threads.
3Question 3.
What guarantees visibility when one thread writes to a volatile variable and another thread reads it?
- The write is delayed
- All writes are synchronized
- The write happens-before the read
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Consider how volatile variables work.
4Question 4.
True or False: Actions before a thread starts are not visible to the thread.
- True
- False
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Revisit the concept of thread start.
Question 5.
Describe how you would use multiple threads to count to 100 and ensure that the correct final count is printed. Include the use of synchronization to ensure visibility of the count.
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Think about thread safety with shared resources.
Question 6.
Given a situation where Thread A modifies a configuration variable while Thread B reads it, illustrate how to structure the code using volatile variables to guarantee current values are seen.
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Focus on the volatile keyword's behavior.

4 more questions in this section. Enroll free to practise them all.