[pentlander]

I started upgrading some of the Docker images from Java 8 to Java 16 at work without touching the compiler. The changes I had to make to the code were fairly minimal, bump the version on a couple libraries and change the JVM flags on the Helm chart. The title is a bit clickbaity, but I agree with the premise for containerized workloads because the difference is huge.

The faster startup is nice, but the biggest advantage is in the memory usage. G1 past Java 8 actually releases memory back to the OS instead of keeping it forever. In addition, I've seen applications use 1/7th of the heap space after upgrading. This translates to being able to significantly lower the memory limits for applications without worrying about OOMing. I haven't moved enough services to see the difference in CPU, but it looks promising there as well.