heroku java 17 enable preview

To enable Java 17 preview in a Heroku app, you can follow these steps:

1. Update the system.properties file in your app's root directory to include the following line:

java.runtime.version=17

This will tell Heroku to use Java 17 as the runtime for your app.

2. In your pom.xml file, update the java.version property to 17:

<properties>
  <java.version>17</java.version>
</properties>

This will ensure that your app is built with Java 17.

3. In your Procfile, specify the Java version by adding the -XX:+UseJava17 flag to the JAVA_OPTS environment variable:

web: java -XX:+UseJava17 -jar target/<your-app>.jar

4. Commit the changes to your Git repository and push the code to Heroku.

Heroku will then build and deploy your app using Java 17. Note that Java 17 is still in preview and may not be fully supported by all features and services on Heroku.

For more information about using different Java versions on Heroku, you can refer to the Heroku documentation (https://devcenter.heroku.com/articles/java-support).