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Dynamic analysis tools with a Java concurrency focus, such as SureLogic Flashlight and Coverity Dynamic Analysis will uncover the race conditions shown in the noncompliant code examples above. To accomplish this, however, these tools would have to observe the noncompliant code being called by two or more threads. Such as in an integration or stress test environment. These tools use a dynamic lockset analysis to detect race conditions. This analysis intersects the set of locks that are observed to be held when each piece of shared state in the program is accessed. If the lockset for a piece of shared state is empty then a race condition may have been observed and the tool reports this to the use.
Static Heurisitics-based static analysis tools, such as FindBugs and PMD, do not detect problems with the noncompliant solutions shown above without some "hint" that the program code is intended to be thread-safe. For example, consider the compliant code below where the use of a synchronized method is a hint to the analysis tool that the class is intended to be used concurrently.
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FindBugs and PMD will not report a warning about this implementation as they do not note any problems.
SureLogic JSure, a an analysis-based verification tool, will complain that the lock is unknown to the tool and ask the user to annotate what state the lock protects, i.e., the tool wants to know the locking policy that the programmer intends for this class. To express this intent, the programmer adds two annotations:
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