Upgrade to Java 21 before Cloud Migration?

[aanchal-sikka]

Hello,

We are currently on AEM 6.5 and planning Cloud Migration.

Noticed that new Cloud onboardings are based on Java 21.

So, if we move to Cloud directly, we would not have Managed Services support for Java 21 migration.

Wondering if we should move Java 21 with 6.5 LTS and then plan for Cloud. Any suggestions? Specially for Assets with Asset Share

Any feedback on challenges faced in Java 21 migration? 

[konstantyn_diachenko]

Hi @aanchal-sikka ,

I've upgraded several projects from Java 11 to Java 21 and we didn’t encounter any critical or major issues during the process. In AEM as a Cloud Service (AEMaaCS), migrating to Java 21 typically involves updating build dependencies only. The infrastructure (environment) is automatically updated as part of the build process.

In contrast, with AEM on-premise, you would need to manually update Java across all environments. Additionally, you'd have to design a deployment/release strategy - such as blue/green deployment - which adds complexity to the migration.

Given these differences, I recommend migrating directly to AEMaaCS with Java 21 to simplify the process and reduce operational overhead.

[aanchal-sikka]

Thanks @konstantyn_diachenko  for sharing your experience. 

[kautuk_sahni]

Great question, @aanchal-sikka! This is something many teams are starting to think through as Java 21 becomes the standard for new Cloud setups. Doing the upgrade on 6.5 LTS first could give you more control and time to validate Asset workflows (especially with Asset Share) before tackling Cloud migration. Curious to hear from anyone who has already gone through Java 21 migration, what challenges did you run into, and what worked well?

[aanchal-sikka]

Thanks for sharing @kautuk_sahni .

I was wondering the same. We have dedicated CSE, so java 21 upgrade on AEM 6.5 LTS might be easier with his help.