Java 21 Lambda Cold Starts: SnapStart vs Provisioned Concurrency vs GraalVM

Cold start mitigation for Java 21 Lambda at 50K RPS is one of the most punishing interview questions for senior cloud engineers — here's how to compare the three real options without hand-waving.

You'll learn:

• How SnapStart snapshots the Afterburner-restored JVM state and where it still adds latency on restore
• Why Provisioned Concurrency keeps execution environments warm but drives up cost at sustained 50K RPS
• Where GraalVM native compilation wins on p99 cold-start time and what you sacrifice in build complexity and reflection support
• How to frame the tradeoff in an interview: cost per invocation, tail latency SLOs, and CI/CD pipeline impact
• Which option AWS recommends for high-throughput workloads and why that answer depends on traffic shape

Keywords: Java Lambda cold start, SnapStart vs provisioned concurrency, GraalVM native Lambda, AWS Lambda 50K RPS, Lambda performance tuning

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