Enable OpenJ9’s SharedClasses Cache

The Eclipse OpenJ9 JVM offers Spring applications significant benefits when deployed as part of a cloud-native runtime. 

OpenJ9 comes with improvements to memory overhead and startup times, achieved through shared classes and an aggressive focus on memory footprint.

To benefit from the startup time improvements, enable OpenJ9's SharedClasses Cache (which enables dynamicAOT), by setting the following JVM options:

-Xshareclasses -Xscmx50M -Xquickstart