1.x: Workaround for CHM.keySet bad type with Java 8 compiler

[akarnokd]

This PR fixes the problem that ConcurrentHashMap::keySet, when compiled on JDK 8, adds the KeySetView type in the bytecode which is not available in JDK 7 and before. The change forces the offending place to use the the standard Map::keySet which returns a standard Set.

[JakeWharton]

👍 !

[artem-zinnatullin]

Let's add a comment I guess

[artem-zinnatullin]

Please give me some time to run test scenario that failed before as a sanity check

[artem-zinnatullin]

Checked with test scenario from artem-zinnatullin/RxJavaProGuardRules#62 (comment)

[artem-zinnatullin]

NoSuchMethodError

[akarnokd]

Updated.

[akarnokd]

Added comment.

I assume if the PR is verified by @artem-zinnatullin, we should release 1.3.2 asap.

[artem-zinnatullin]

mkay, looks like Travis stuck, build is in the queue for an hour.

@akarnokd can you stop/start or retrigger it?

[akarnokd]

There is quite a backlog piled up on Travis. May not clear before I go to sleep.

[artem-zinnatullin]

Ok, you might want to check "Concurrent jobs" related options in build settings on Travis

[akarnokd]

It's not our single job but an overall ~400 started by other projects:

[codecov]

Codecov Report

Merging #5602 into 1.x will decrease coverage by 0.13%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##                1.x    #5602      +/-   ##
============================================
- Coverage     84.34%   84.21%   -0.14%     
+ Complexity     2891     2886       -5     
============================================
  Files           291      291              
  Lines         18198    18199       +1     
  Branches       2480     2480              
============================================
- Hits          15349    15326      -23     
- Misses         1989     1999      +10     
- Partials        860      874      +14

Impacted Files	Coverage Δ	Complexity Δ
...n/java/rx/internal/schedulers/NewThreadWorker.java	59.43% <0%> (-0.57%)	20 <0> (ø)
...java/rx/internal/schedulers/ExecutorScheduler.java	77.46% <0%> (-7.05%)	2% <0%> (ø)
...al/schedulers/GenericScheduledExecutorService.java	70.73% <0%> (-4.88%)	12% <0%> (ø)
...ain/java/rx/internal/schedulers/SchedulerWhen.java	83.78% <0%> (-4.06%)	4% <0%> (ø)
...va/rx/internal/schedulers/EventLoopsScheduler.java	84.84% <0%> (-3.04%)	7% <0%> (ø)
src/main/java/rx/observers/SerializedObserver.java	97.82% <0%> (-2.18%)	19% <0%> (-1%)
.../rx/internal/schedulers/CachedThreadScheduler.java	89.32% <0%> (-1.95%)	6% <0%> (ø)
...x/internal/operators/DeferredScalarSubscriber.java	98.27% <0%> (-1.73%)	24% <0%> (-1%)
...a/rx/internal/operators/BufferUntilSubscriber.java	71.42% <0%> (-1.59%)	11% <0%> (-1%)
...n/java/rx/subjects/SubjectSubscriptionManager.java	80.71% <0%> (-1.43%)	15% <0%> (-1%)
... and 8 more

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