EAP6 with adapter running on JDK 7 twrows following error:

ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 3) JBAS014612: Operation ("add") failed - address: ([("extension" => "org.keycloak.keycloak-adapter-subsystem")]): java.lang.UnsupportedClassVersionError: org/keycloak/subsystem/as7/KeycloakExtension : Unsupported major.minor version 52.0
13:23:32 at java.lang.ClassLoader.defineClass1(Native Method) [rt.jar:1.7.0_79]
13:23:32 at java.lang.ClassLoader.defineClass(ClassLoader.java:800) [rt.jar:1.7.0_79]