This is a demo project to show some new features of Java™ 21. (For previous version go to DeepDiveJava20.)
It uses --enable-preview and Maven, but you don't need to have Maven installed.
To run this project, you need to have Java™ 21 installed. You can use https://sdkman.io/ and/or https://openjdk.java.net/, https://adoptium.net/
If you'd like to run the example app, one of the options is this:
$ MAVEN_OPTS="--enable-preview" ./mvnw exec:java -pl goodies
(If it doesn't work, you might have Java 21 not installed.)