hello-graal

Hello Graal Java Example

This is a "Hello Graal" Java example for GraalVM. The structure of the Hello package is like this:

.
| src
|   `--com/
|      `-- hello
|          `-- Graal.java
|-- LICENSE
|-- .gitignore
|-- manifest.txt
`-- README.md

Preparation

1. Download and install the latest GraalVM JDK using SDKMAN!.

   sdk install java 21.0.1-graal

2. Download or clone GraalVM demos repository and navigate into the hello-graal directory:

   git clone https://github.com/graalvm/graalvm-demos

   cd graalvm-demos/hello-graal

Running the Application from a Class File

1. Compile the application running the follow command:

   $JAVA_HOME/bin/javac -d build src/com/hello/Graal.java

   This generates the Graal.class file into build/com/hello directory.

2. Run the application from a class file:

   $JAVA_HOME/bin/java -cp ./build com.hello.Graal

   It outputs the message "hello graal".

Running the Application from JAR

1. Create a JAR for the application, running the follow command:

   $JAVA_HOME/bin/jar cfvm Hello.jar manifest.txt -C build .
   jar tf Hello.jar

   The output will be:

   META-INF/
   META-INF/MANIFEST.MF
   com/
   com/hello/
   com/hello/Graal.class

2. Run the JAR file:

   $JAVA_HOME/bin/java -jar Hello.jar

   It outputs the message "hello graal".

Running the Application as a Native Executable

1. Create a native executable of a JAR file:

   $JAVA_HOME/bin/native-image -jar Hello.jar

   The executable called ./Hello will be created in the working directory.

2. Execute it:

   ./hello

   It outputs the message "hello graal". To check the filesize of the executable image, run: ls -lh Hello.

References

1. Creating a JAR File
2. Setting an Application's Entry Point
3. How to create a Native Image