Oracle GraalVM in OCI Code Editor

This guide shows you how to get started with Oracle GraalVM in Oracle Cloud Infrastructure (OCI) Code Editor.

OCI Code Editor provides a rich, in-console editing environment that enables you to edit code without having to switch between the Oracle Cloud Console and your local development environment. The Code Editor enables you to edit and deploy code for OCI services directly from the OCI Console.

Oracle GraalVM for JDK 17 is preinstalled in Cloud Shell, so you do not have to install and configure a development machine. Code Editor’s integration with Cloud Shell gives you direct access to it.

Create and Run a Java Application in OCI Code Editor

Step 1: Open a Terminal in Code Editor

Login to the Oracle Cloud Console and launch Code Editor.
Open a Terminal in Code Editor, by clicking New Terminal from the Terminal menu.

Step 2: Select GraalVM JDK as the Default JDK

List the installed JDKs using the csruntimectl java list command.
```
 csruntimectl java list
```
The output lists the JDKs preinstalled in Cloud Shell: Oracle GraalVM for JDK 17, Oracle JDK 11, and Oracle JDK 8. The JDK marked with an asterisk is the current JDK.
Select Oracle GraalVM for JDK 17 as the current JDK:
```
 csruntimectl java set graalvmjdk-17
```
You will see the confirmation message printed: “The current managed java version is set to graalvmjdk-17”.
Now confirm the values of the environment variables PATH and JAVA_HOME, and the versions of java and the native-image tool:
```
 echo $JAVA_HOME
```
```
 echo $PATH
```
```
 java -version
```
```
 native-image --version
```

Step 3: Setup a Java Project and Run

Clone a demo repository and open it in OCI Code Editor. To achieve this, run the following commands one by one:

 git init graalvmee-java-hello-world

 cd graalvmee-java-hello-world

 git remote add origin https://github.com/oracle-devrel/oci-code-editor-samples.git

 git config core.sparsecheckout true

 echo "java-samples/graalvmee-java-hello-world/*">>.git/info/sparse-checkout

 git pull --depth=1 origin main

 cd java-samples/graalvmee-java-hello-world/

You can now view/edit the sample code in Code Editor.

Package the sample application into a runnable JAR file:
```
 mvn clean package
```
Run the JAR file:
```
 java -jar target/my-app-1.0-SNAPSHOT.jar
```
It prints out “Hello World!”.

Step 4: Build and Run a Native Executable

This Java application incorporates the Maven plugin for GraalVM Native Image that adds support for building native executables using Apache Maven. For testing purposes, build a native executable with the quick build mode first enabled and then disabled.

Quick Build Mode Enabled

To enable the quick build mode, uncomment this line in pom.xml, as follows:
```
 <quickBuild>true</quickBuild>
```
Build a native executable using the native Maven profile:
```
 mvn clean -Pnative -DskipTests package
```
This will generate a native executable for Linux in the target directory, named my-app.
Run the app native executable in the background:
```
 ./target/my-app
```

Quick Build Mode Disabled

To disable the quick build mode, comment out this line in pom.xml, as follows:
```
 
```
Build a native executable again:
```
 mvn clean -Pnative -DskipTests package
```
This will generate a native executable, my-app, in the target directory, replacing the previous one. You have probably noticed how the quick build mode reduced the time required to generate a native executable, making it easier to use Native Image in a typical development cycle (compile, test, and debug). However, the size of a generated executable is larger and peak performance is worse. The quick build mode is recommended for development purposes only.
Run the native executable:
```
 ./target/my-app
```

Congratulations! You have successfully built and run a native executable using Oracle GraalVM in OCI Code Editor without the need to switch between the Oracle Cloud Console and your local development environments. The Code Editor allows you to accomplish quick coding tasks and run applications directly from the OCI Console.