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To gain better ability at telling apart correct from fallacious results and enforcing that the incorrect results be carefully handled, a combination of the aforementioned approaches is recommended. At the same time, there are cases when an error value should be returned instead of an exception and vice versa. For instance, if some method is capable of failing in a variety of different ways, it is better to return failure codes than endeavoring to throw scores of different exceptions. Not that no possible failure codes should be within the range of valid return values.
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Sometimes a state testing method \[[Bloch 08|AA. Java References#Bloch 08]\] can be used to ensure that the object is in consistent state at all points in time. This approach is not useful in the absence of external synchronization. Also, there is a TOCTOU race condition between invocation of the object's state testing method and the call to a method that depends on its state. During this interval, the object could change surreptitiously. |
Noncompliant code example
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