Lessons Learned from Upgrading and Modernizing a Massive JVM Codebase at AWS by Volker Simonis

As one of the largest Java users in the world, Amazon has been on a perpetual journey of upgrading Java versions in it's production systems and for the last 7 years also contributed to the evolution of the JVM. In this talk, we will share our experiences and lessons learned from migrating a large codebase running on massive infrastructure from Java 7 to 8, 11, 17, and even 21.

We'll cover key technical challenges we faced in upgrading our codebase while maintaining availability and improving performance, including dependencies, observability, and platform compatibility. We'll share which investments paid off, where we're still struggling, and the archaic parts of Java we wish we could leave behind.

You'll learn about:

The scale and diversity of AWS's internal Java ecosystem
How we manage the effort of migrating to Java 17
What hurdles we fixed, jumped over, and which still remain
How observability, profiling, and modularization are critical
Lessons for modernizing your own large-scale Java backend
Coping with device world

If you want an inside look at our modernization war stories from the Amazon trenches, come listen Volker Simonis, Principal Software Developer for Languages and Runtime at AWS.

Volker Simonis
Amazon Web Services (AWS)

Recorded at Jfokus 2024 in Stockholm 7th of february