PR Stack (SDK Overhead Reduction)

• perf(core): SDK Overhead Reduction #5499
• perf(core): [SDK Overhead Reduction 1] Skip java.specification.version lookup on Android #5500
• perf(android): [SDK Overhead Reduction 2] Replace reflective OptionsContainer with direct subclass #5501
• perf(android): [SDK Overhead Reduction 3] Reuse SentryExecutorService for DeviceInfoUtil pre-caching #5502
• perf(android): [SDK Overhead Reduction 4] Use default timezone directly #5587
• perf(core): [SDK Overhead Reduction 5] Replace Calendar with Date in DateUtils #5589
• perf(core): [SDK Overhead Reduction 6] Reduce JsonWriter stack allocation #5591
• perf(core): [SDK Overhead Reduction 7] Lazily allocate Breadcrumb data #5598
• perf(core): [SDK Overhead Reduction 8] Reduce context serialization allocations #5599
• perf(core): [SDK Overhead Reduction 9] Lazily allocate reflection serializer state #5600
• perf(core): [SDK Overhead Reduction 10] Lazily create reflection JSON serializer #5601
• perf(core): [SDK Overhead Reduction 11] Replace ISO8601 timestamp handling #5602

📜 Description

Replace the normal Android device timezone path with TimeZone.getDefault() instead of constructing a Calendar just to read its timezone.

One compatibility detail is preserved: Android 13+ Calendar.getInstance(locale) can honor a locale Unicode tz extension (for example en-US-u-tz-usnyc). For those rare locales, the code keeps the Calendar path so the SDK continues reporting the same timezone as before. On Android N through Android 12, and for normal locales without a tz extension, the locale did not affect the timezone value.

💡 Motivation and Context

Part of the SDK Overhead Reduction stack. In the common case, device context collection only needs the process default timezone. TimeZone.getDefault() is available on Android API 21 and Java 8, and avoids constructing a Calendar and reading locale configuration just to retrieve the same timezone.

The previous API 24+ branch used the first Configuration locale, but Android N through Android 12 did not use that locale to select the timezone. Android 13 added tz Unicode extension support to Calendar.getInstance(locale), so this PR preserves that behavior with a narrow fallback while keeping the fast direct-default path for all other cases.

💚 How did you test it?

• ./gradlew :sentry-android-core:testDebugUnitTest --tests io.sentry.android.core.DeviceInfoUtilTest — all tests pass
  • includes regression coverage for an Android 13+ locale with a Unicode tz extension (en-US-u-tz-usnyc)
• ./gradlew spotlessApply apiDump — no API surface changes

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

More SDK overhead reduction PRs in this stack.

#skip-changelog

⚠️ Merge this PR using a merge commit (not squash). Only the collection branch is squash-merged into main.