Programmers sometimes assume that composite operations on primitive data are atomic. However, this is not true in a multithreaded environment. Even code that does not involve a composite operation can be nonatomicunsafe for use, for instance:
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x = 3; |
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For instance, if a and b currently have the value 0, and one thread calls getSum() while another calls setValues(1, 1), then getSum() might return 0, 1, or 2. Of these, the value 1 is unacceptable; it is returned when the first thread reads a and b after the second thread has set the value of a but before it has set the value of b.
Compliant Solution
This compliant solution provides synchronizes the setValues() method so that the entire operation is atomic.
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