Java error on election-orchestra deploy

[nfortea]

When i execute on auth1 and auth2:
time sudo ansible-playbook -i inventory playbook.yml
I get a error:

TASK [EOrchestra, vfork init random device] ************************************
fatal: [localhost]: FAILED! => {"changed": true, "cmd": "bash -l -c \"source /home/eorchestra/.vfork_env && vog -rndinit RandomDevice /dev/urandom\"", "delta": "0:00:00.235648", "end": "2017-06-26 12:42:13.241989", "failed": true, "rc": 1, "start": "2017-06-26 12:42:13.006341", "stderr": "Exception in thread \"main\" java.lang.UnsupportedClassVersionError: vfork/ui/gen/GeneratorTool : Unsupported major.minor version 52.0\n\tat java.lang.ClassLoader.defineClass1(Native Method)\n\tat java.lang.ClassLoader.defineClass(ClassLoader.java:803)\n\tat java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)\n\tat java.net.URLClassLoader.defineClass(URLClassLoader.java:442)\n\tat java.net.URLClassLoader.access$100(URLClassLoader.java:64)\n\tat java.net.URLClassLoader$1.run(URLClassLoader.java:354)\n\tat java.net.URLClassLoader$1.run(URLClassLoader.java:348)\n\tat java.security.AccessController.doPrivileged(Native Method)\n\tat java.net.URLClassLoader.findClass(URLClassLoader.java:347)\n\tat java.lang.ClassLoader.loadClass(ClassLoader.java:425)\n\tat sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:312)\n\tat java.lang.ClassLoader.loadClass(ClassLoader.java:358)\n\tat sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)", "stdout": "", "stdout_lines": [], "warnings": []}

Despite Im using oracle-java8-installer.

Can you help me?