Summary:
Prior to this the native library loader instance didn`t
care about a state. So if library loading was called multiple
times, multiple copies of the shared object were put into
the tmp folder and loaded into the JVM.
This changed within this commit to the following behavior:
- library loading is now synchronized
- library is loaded within the first call
- if loading was successful the library loaded sets a flag
- every subsequent call checks for a boolean flag indicating if there was
already a successful attempt
Test Plan:
- Execute example and watch tmp folder while the example is running
- After this patch only one shared object will be in the tmp folder
Usual tests:
- make rocksdbjava jtest
- mvn -f rocksjni.pom package
Reviewers: adamretter, ankgup87, yhchiang
Subscribers: dhruba
Differential Revision: https://reviews.facebook.net/D32133
e61f38e5a0