GraalVM + AWS Lambda or solving Java cold start problem

Aleksandr Filichkin
4 min readAug 14, 2021

Do you also like Serverless and Java, but hate a Java code start? In this article, we are going to demonstrate how to solve Java cold start issue in AWS Lambda.

Let’s write some book microservice and measure the performance.

As usual all code you can see in my Github:

Our test architecture

API-Gateway -> AWS Lambda->DynamoDb

Version 1 (plain Java without improvements)

  • Java 11
  • AWS SDK-V2 for DynamoDB(extended DynamoDb client)
  • No DI (Spring, Dagger, etc)
  • No special frameworks

Code is here

Our handler is:


REPORT RequestId: e89b743e-bf08–4c8a-9783–0772102d4e90 Duration: 10845.21 ms Billed Duration: 10846 ms Memory Size: 256 MB Max Memory Used: 168 MB Init Duration: 2650.86 ms

Cold start for version 1 (256 Mb)

Version 2(plain Java with improvements)

  • Java 11
  • AWS SDK-V2 for Dynamodb
  • No DI (Spring, etc)
  • No special frameworks
  • Utilize CPU burst on startup (move everything to static, warm-up dynamoDB client)
  • Reduce dependencies(exclude Netty)
  • Specify AWS Regions
  • Specify Credential Provider

Code is here: