Multithreading demo is provided to showcase the applicability of GraalVM Dashboard - a web-based dashboard for visualizing aspects of dynamic and static compilations in GraalVM, in particular, Native Image.

The demo is a Java program which does synchronous and asynchronous threads execution. Each thread loops through exactly the same array of integers and generates a stream of pseudorandom numbers. The program calculates the time taken to perform the task synchronously and asynchronously.

Multithreading demo is comprised of two sub-projects, each built with Maven: Multithreading Demo Oversized and Multithreading Demo Improved. The pom.xml file of each sub-project includes the Native Image Maven plugin, which instructs Maven to generate a native image of a JAR file with all dependencies at the mvn package step. The plugin will also gather the diagnostic information during the native image build and write that data to a dump file in the target directory.

<plugin>
    <groupId>org.graalvm.nativeimage</groupId>
    <artifactId>native-image-maven-plugin</artifactId>
    <version>${graalvm.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>native-image</goal>
            </goals>
            <phase>package</phase>
        </execution>
    </executions>
    <configuration>
        <skip>false</skip>
        <imageName>multithreading-image</imageName>
        <buildArgs>
            --no-fallback -H:DashboardDump=dumpfile -H:+DashboardAll --initialize-at-build-time
        </buildArgs>
    </configuration>
</plugin>

To build and run the projects, you can either use GraalVM, or any other JDK distribution.

1. Download or clone the repository and navigate into the multithreading-demo/multithreading-demo-oversized directory:

git clone https://github.com/graalvm/graalvm-demos
cd multithreading-demo/multithreading-demo-oversized

2. Build the project:

mvn package

3. Run the project on a JVM or as a native image:

java -jar target/multithreading-1.0-jar-with-dependencies.jar
./target/multithreading-image-oversized

Multithreading Demo Improved contains an enhanced version of the same program.

1. Change to the project directory:

cd ..
multithreading-demo-improved

2. Build the project:

mvn package

3. Run the project on a JVM or as a native image:

java -jar target/multithreading-1.0-jar-with-dependencies.jar
./target/multithreading-image-improved