Class Data Sharing

Class Data Sharing (CDS) is a JVM feature that can help reduce the startup time and memory footprint of Java applications.

To use it, you should first perform a training run on your application in extracted form:

$ java -Djarmode=tools -jar my-app.jar extract --destination application
$ cd application
$ java -XX:ArchiveClassesAtExit=application.jsa -Dspring.context.exit=onRefresh -jar my-app.jar

This creates an application.jsa file that can be reused as long as the application is not updated.

To use the cache, you need to add an extra parameter when starting the application:

$ java -XX:SharedArchiveFile=application.jsa -jar my-app.jar

For more details about CDS, refer to the CDS how-to guide and the Spring Framework reference documentation.