frant-hartm
commented
6 years ago Hi,
we are aware it is not thread-safe. It is used in places as a cache to replace multiple expensive calls returning same result to just one (or a few) calls.
The LazyInstance class should not be used from user's code.
So I am closing. If this causes real issue feel free to reopen with a test case.
Expected Behavior
LazyInstance should be thread safe. Calling LazyInstance.get() from multiple theads should create only a single instance in one thread and all threads should receive this instance.
Current Behavior
If multiple threads call get on a LazyInstance object, they may not get already initialized instance due to thread local cache and create a new copy of instance.
Possible Solution
To fix this one can make use of AtomicMarkableReference to update initialized flag and instance in an atomic operation. The following commit contains the required change. https://github.com/rcodekaran/neo4j-ogm/commit/979567f2ab5ba6c2ec041436ea77692accceeb22
Steps to Reproduce (for bugs)
Create around 100 threads and call on a single LazyInstance object and count the number of times a new instance gets created.