1Z0-829: Java SE 17 DeveloperDemo

Question

Given the following code fragments:

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and

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Which statement is correct?

A The program prints t1 : 1 : t2 : 1: t1 : 2 : t2 : 2 : in random order.
B The program prints t1 : 1 : t2 : 1: t1 : 2 : t2 : 2 :
C The program prints t1 : 1 : t2 : 1: t1 : 1 : t2 : 1 : indefinitely.
D The program prints an exception.

Explanation

The volatile x is read and incremented only by t1, so t1 outputs 1 and 2. AtomicInteger.get() reads the current value and getAndIncrement() atomically increments it, so t2 outputs 1 and 2 before its loop terminates at 3. Because the threads run concurrently, their output calls may interleave in a scheduling-dependent order. Oracle documents that AtomicInteger.get() reads the current value and that getAndIncrement() atomically increments it.

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AtomicInteger (Java SE 25)

1Z0-829: Java SE 17 DeveloperDemo

AstroTutor

Notes

Readiness

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