* make Pair immutable and in google-code-style
* apply google-code-style to JavaTimeFormatter (to make it consistent with most other auto-generated java)
* move upperCaseBearer to ctor (scheme is final and private; only needs to be fixed once); also replaced Optional with ternary (perf and cleaner code)
* apply google-code-style to Authentication to make it consistent with rest of auth code
* fresh samples
* Make all Java ApiClients in templates extendable
* Make all Java ApiClients in samples extendable
* Fix compilation of enum constructor
* Fix compilation of enum constructor in templates
* issue-20804: Add nullability annotations to Java generated clients
Motivation:
Be able to use generated clients in code checked by tools like NullAway.
* issue-20804: Add nullability annotations to Java generated clients
Motivation:
Be able to use generated clients in code checked by tools like NullAway.
* issue-20804: Add nullability annotations to Java generated clients
Motivation:
Be able to use generated clients in code checked by tools like NullAway.
* made Configuration.defaultApiClient volatile so that if it's changed the new value is immediately visible to all other threads
* made no-arg api ctor use Configuration.getDefaultApiClient() instead of creating new ApiClient every time
* replaced all use of URLEncoder.encode with ApiClient.urlEncode; just code cleanup; no functional changes
* disabled AbstractJavaCodegenTest.testGeneratedExampleValues as it fails, possibly due to timezone (Locale.ROOT) of local system
* replaced thread-unsafe SimpleDateFormat with DateTimeFormatter and re-enabled unit-test
* removed unused import
* ran the generate-sample scripts and generated a HUGE number of changes!
* added missing import of Configuration to api.mustache (and, thus, all native samples)
* added missing import for ApiClient to anyof and oneof model mustaches
