(1) FIFOReadWriteLock -
* Interference: line 84 (readers incremented without holding onto a lock)
* Deadly embrace: acquireRead (lines 52-55) acquires lock of this followed by
entryLock
whilst acquireWrite (lines 64-72) acquires entryLock followed by this

(2) Mutex -
* Interference: line 29 (in_use changed without holding onto a lock)
* Encapsulation of shared variables: line 21 (in_use is protected and not
private and therefore can be modified outside this class)
* Wait not in loop: line 27
* Wait condition incorrect: line 52 (it should be if (!in_use) and then in_use
can be set to true)

(3) ReaderWriterSync -
* Lock reassignment: line 52 (readLock=writeLock;)
* Deadly embrace: safeReleaseRead (lines 29-36) acquires readLock and then
writeLock, whilst safeReleaseWrite (lines64-72) acquires writeLock and then
readLock

(4) Piper -
* Wait not in loop: line 47
* notify instead of notifyAll: line 55