148. Lambda and Java with Mark Sailes

AWS Bites

What if “Java is too old for serverless” is the myth holding your team back in 2025?

We put it to the test with Mark Sailes (ex-AWS, Java-on-Lambda expert). In this AWS Bites episode we get specific: when Java is the right call for Lambda and when it isn’t, how to hit real latency targets, and the exact levers that matter in production—SnapStart, provisioned concurrency, smart JVM/GC settings, and whether GraalVM is worth it. We compare vanilla Java, Micronaut, Quarkus, and Spring Boot for startup and memory, share realistic p95/p99 expectations, and outline fast feedback loops with Testcontainers and LocalStack.If Java on Lambda sounds risky, this might change your mind. Stick around for Mark’s tuning checklist and our verdict on when to bet on Java vs pick another runtime.

Big shoutout to fourTheorem for powering yet another episode of AWS Bites. At fourTheorem, we believe the cloud should be simple, scalable, and cost-effective, and we help teams do just that. Whether you’re diving into containers, stepping into event-driven architecture, or scaling a global SaaS platform on AWS, or trying to keep cloud spend under control our team has your back. Visit ⁠⁠⁠⁠https://fourTheorem.com⁠⁠⁠⁠ to see how we can help you build faster, better, and with more confidence using AWS cloud!

In this episode, we mentioned the following resources:

• Mark Sailes's website and books: https://www.sailes.co.uk/books
• Mark's YouTube channel: https://youtube.com/@javainthecloud
• Running Java effectively on serverless (ServerlessLand): https://serverlessland.com/content/service/lambda/guides/effectively-running-java-on-serverless/1-introduction
• Lambda execution visualizer: https://lambda-sim.sailes.co.uk/
• Lambda SnapStart for Java simulator: https://www.sailes.co.uk/learn/lambda-snapstart
• Penna logging library for Java: https://github.com/hkupty/penna
• Testcontainers for Java: https://java.testcontainers.org/
• Localstack: https://docs.localstack.cloud/aws/
• Micronaut: https://micronaut.io/
• Quarkus: https://quarkus.io/
• GraalVM: https://www.graalvm.org/
• AWS response to the Log4j issue: https://aws.amazon.com/security/security-bulletins/AWS-2021-005/

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