ngadde / spring-cds-demo

Demonstrate how to use Spring Framework 6.1 CDS support

Spring CDS demo

This repository is intended to demonstrate how to use Spring Framework 6.1 CDS support.

See also:

• https://github.com/sdeleuze/spring-petclinic-data-jdbc/tree/cds for related Spring Petclinic data points
• https://github.com/snicoll/cds-log-parser which allows to produce a report about class loading
• spring-boot#38276 Improve exploded structure experience for efficient deployments
• spring-boot#34115 Investigate automatic CDS support

Pre-requisites

While it is possible to use Java 17, it is recommended to use Java 21 which provide a more advanced CDS support. You should also use a Java distribution with a prebuilt CDS archive.

You can use SDK manager to install and use such Java distribution:

sdk env install
sdk env

Check the application starts correctly without CDS involved:

./gradlew bootRun

Check the startup time, for example on my MacBook Pro M2:

Started CdsDemoApplication in 0.575 seconds (process running for 0.696)

Build and run with CDS

You can either just run the cds.sh script and perform those steps manually.

Build the project.

./gradlew build

Unpack the Spring Boot application to a JAR structure suitable for optimal performances with CDS:

./unpack-executable-jar.sh -d build/unpacked build/libs/cds-demo-0.0.1-SNAPSHOT.jar

This should create the following JAR structure:

build
└── unpacked
        ├── application
        │   └── spring-cds-demo-1.0.0-SNAPSHOT.jar
        ├── dependencies
        │   ├── ...
        │   ├── spring-context-6.1.0.jar
        │   ├── spring-context-support-6.1.0.jar
        │   ├── ...
        └── run-app.jar"

Perform the CDS training run (here with Spring AOT optimizations) in order to create an additional build/unpacked/application.jsa file:

java -Dspring.aot.enabled=true \
-Dspring.context.exit=onRefresh \
-XX:ArchiveClassesAtExit=build/unpacked/application.jsa \
-jar build/unpacked/run-app.jar

And finally run the application with CDS optimizations (here with Spring AOT optimizations):

java -Dspring.aot.enabled=true \
-XX:SharedArchiveFile=build/unpacked/application.jsa \
-jar build/unpacked/run-app.jar

Check the startup time, for example on my MacBook Pro M2:

Started CdsDemoApplication in 0.289 seconds (process running for 0.384)

Build and run optimized container images CDS

Check content of the Dockerfile and run the create-container-image.sh script, or run manually:

docker build -t sdeleuze/spring-cds-demo .

Then run the run-container.sh script, or run manually:

docker run --rm -it -p 8080:8080 sdeleuze/spring-cds-demo

You can also try to deploy the resulting container image to your Cloud or Kubernetes platform. Make sure that the server where you deploy the application has the same CPU architecture than the one where you built the CDS archive.