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Volatile variables are unsuitable when more than one read/write operation needs to be atomic. The use of a volatile variable in this noncompliant code example guarantees that once itemsInInventory has been updated, the new value is immediately visible to all threads that read the field. However, because the post decrement operator is nonatomic, even when volatile is used, the interleaving described in the previous noncompliant code example is still possible.
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Code that uses this lock behaves similar to synchronized code that uses the traditional monitor lock. ReentrantLock provides several other capabilities, for instance, the tryLock() method does not block waiting if another thread is already holding the lock. The class java.util.concurrent.locks.ReentrantReadWriteLock can be used when some thread requires a lock to write information while other threads require the lock to simultaneously concurrently read the information.
Noncompliant Code Example (addition)
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