A minimal application for demostrating application class-data sharing (AppCDS). This repository is referenced from the following HappyCoders article on new features in Java 10:

• English: Java 10 Features (With Examples)
• German: Java 10 Features (mit Beispielen)

You need at least Java 10, preferably OpenJDK, since AppCDS is a commercial feature in the Oracle JDK.

To run the application using AppCDS, follow these steps:

Compile and package the code.

javac -d target/classes src/eu/happycoders/appcds/*.java
jar cf target/helloworld.jar -C target/classes .

Create a list of classes that the application uses.

(On Windows, you must omit the backslashes and write everything on one line.)

java -Xshare:off -XX:+UseAppCDS \
    -XX:DumpLoadedClassList=helloworld.lst \
    -cp target/helloworld.jar eu.happycoders.appcds.Main

As the program is executed to created the class list, you should see a "Hello world!".

Create a JSA file (Java shared archive) from the class list.

java -Xshare:dump -XX:+UseAppCDS \
    -XX:SharedClassListFile=helloworld.lst \
    -XX:SharedArchiveFile=helloworld.jsa \
    -cp target/helloworld.jar

Run the application with the AppCDS activated.

java -Xshare:on -XX:+UseAppCDS \
    -XX:SharedArchiveFile=helloworld.jsa \
    -cp target/helloworld.jar eu.happycoders.appcds.Main

You should see "Hello world!" again.