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Thomas Wolf 0f442d7083 Use Map interface instead of ConcurrentHashMap class On Android, the co-variant override of ConcurrentHashMap.keySet() introduced in Java 8 was undone. [1] If compiled Java code calls that co-variant override directly, one gets a NoSuchMethodError exception at run-time on Android. Making the code call that method via Map.keySet() side-steps this problem. This is similar to bug 496262, where the same problem cropped up when compiling with Java 8 against a Java 7 target, but here we cannot use bootclasspath. We build against Java 8, not against the Android version of it. Recent Android versions should have some bytecode "magic" that adds the co-variant override in bytecode (see the commit referenced in [1]), but on older Android version this problem may still occur. (Or perhaps the "magic" is ineffective...) There are two pull requests on Github for this problem, both from 2020, [2][3] while the Android commit [1] is from March 2018. Apparently people still occasionally run into this problem in the wild. [1] `0e8b937ded/ojluni/src/main/java/java/util/concurrent/ConcurrentHashMap.java (1244)` [2] https://github.com/eclipse/jgit/pull/104 [3] https://github.com/eclipse/jgit/pull/100 Change-Id: I7c07e0cc59871cb7fe60795e22867827fa9c2458 Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>	3 years ago
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http	Use Map interface instead of ConcurrentHashMap class	3 years ago

Thomas Wolf 0f442d7083 Use Map interface instead of ConcurrentHashMap class

On Android, the co-variant override of ConcurrentHashMap.keySet()
introduced in Java 8 was undone. [1] If compiled Java code calls that
co-variant override directly, one gets a NoSuchMethodError exception
at run-time on Android.

Making the code call that method via Map.keySet() side-steps this
problem.

This is similar to bug 496262, where the same problem cropped up when
compiling with Java 8 against a Java 7 target, but here we cannot use
bootclasspath. We build against Java 8, not against the Android version
of it.

Recent Android versions should have some bytecode "magic" that adds the
co-variant override in bytecode (see the commit referenced in [1]), but
on older Android version this problem may still occur. (Or perhaps the
"magic" is ineffective...) There are two pull requests on Github for
this problem, both from 2020, [2][3] while the Android commit [1] is
from March 2018. Apparently people still occasionally run into this
problem in the wild.

[1] 0e8b937ded/ojluni/src/main/java/java/util/concurrent/ConcurrentHashMap.java (1244)
[2] https://github.com/eclipse/jgit/pull/104
[3] https://github.com/eclipse/jgit/pull/100

Change-Id: I7c07e0cc59871cb7fe60795e22867827fa9c2458
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

3 years ago

http Use Map interface instead of ConcurrentHashMap class 3 years ago