Since WildFly 8.1.0.Final was just released, the OpenShift WildFly cartridge has been updated as well and now includes support for Java 8! The WildFly cartridge now installs JDK 8 during instance creation since JDK 8 isn't available on OpenShift yet. All new WildFly applications on OpenShift will default to using Java 8. If you want to switch back to Java 7, simply rename the marker file in your application's git repo as follows:

git mv .openshift/markers/java8 .openshift/markers/java7
git commit -a -m "Switching to Java 7"
git push

If you create a WildFly application based on an existing WildFly 8.0.0.Final or 8.1.0.CR1 OpenShift application using the --from-app command, your new WildFly 8.1.0.Final application will remain on Java 7. You can manually switch to Java 8 as follows:

1. In the pom.xml file in your application's git repo:

Change the maven.compiler.source and maven.compiler.target properties to:

<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>

Add the following two properties:

<maven.compiler.executable>${env.OPENSHIFT_WILDFLY_DIR}usr/lib/jvm/jdk1.8.0_05/bin/javac</maven.compiler.executable>
<maven.compiler.fork>true</maven.compiler.fork>

2. Now rename the marker file and push your changes:

git mv .openshift/markers/java7 .openshift/markers/java8
git commit -a -m "Switching to Java 8"
git push

For more information on how to get started with the WildFly cartridge, take a look at the cartridge documentation. As always, feedback is welcome on the WildFly community forums. Enjoy!