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The Java Language Specification also permits reads and writes of 64-bit values to be non-atomic. ( For more information, see CON25-J. Ensure atomicity when reading and writing 64-bit values.)
Noncompliant Code Example (Logical Negation)
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As a result, the effect of the call by t2 is not reflected in flag; the program behaves as if the call was never made toggle() was called only once, not twice.
Noncompliant Code Example (Bitwise Negation)
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The getSum() method contains a race condition. For example, if a and b currently have the values 0 and Integer.MAX_VALUE, respectively, and one thread calls getSum() while another calls setValues(Integer.MAX_VALUE, 0), getSum() might return 0 or Integer.MAX_VALUE, or it might overflow and wrap. Overflow will occur when the first thread reads a and b, after the second thread has set the value of a to Integer.MAX_VALUE, but before it has set the value of b to 0.
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The simple replacement of the two int fields with atomic integers in this example does not eliminate the race condition because the compound operation a.get() + b.get() is still non-atomic.
Compliant Solution (Addition)
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