Consider Caffeine for Caching to Replace Guava After EOL of Java 7 Support

[tbradellis]

Feature/Problem

Replace our Guava dependency with Caffeine
We, not infrequently (support ticket searchable with thread dumps), run into deadlocks originating from guava caching.
Remediation is generally to disable the instrumentation point.

Feature Description

We use guava 28.2-android in order to Support Java 7. Java 7 support is scheduled for EOL soon. #220

Caffeine requires 1.8+ ben-manes/caffeine#51

We should consider switching dependencies once Java 7 Support is EOL.

The guava maintainers even recommend switching to caffeine for caching.
google/guava#3700 (comment)

Many more examples:

• best Cache pattern for freezing keys on miss? google/guava#3972 (comment)
• LocalCache computeIfAbsent updates write timestamp on existing entries, affecting expireAfterWrite caches google/guava#3700 (comment)
• Can LoadingCache reset expire time? google/guava#3667 (comment)
• Thread lock in LocalCache.lockedGetOrLoad google/guava#3602 (comment)
• size limits for performance google/guava#3506 (comment)
• Active key eviction count google/guava#3427 (comment)
• Change size-based eviction to allow for significantly varying segment sizes google/guava#1854 (comment)
• Cache.getAll fails to trigger refresh google/guava#971 (comment)

Describe Alternatives

Continue using guava and disable instrumentation points as needed when issues arise.
Use some other caching library besides caffeine or guava for caching weave extensions

Priority

Nice to Have, for some this could be a MUST Have issue if key instrumentation is lost when disabling modules to workaround a deadlock.

[Stephan202]

@tbradellis since we discussed this topic in a private support ticket I decided to have a look at what would be involved. The result is #286. Would be nice if a New Relic engineer could schedule some time for a look :)