[keycloak-user] Keycloak Tomcat 7 adaptor - Java version requirement?

[shimin q]

Hi,
I am trying to use keycloak to secure six web apps deployed in Tomcat 7.  Is there a Java version requirement for the keycloak client adaptor?  We are running Tomcat 7 with Java 7.  The keycloak version is 2.1.0.  The strange thing is that not every web app under the tomcat 7 has this error.  They are all compiled similarly and running in the same Tomcat with JRE 7.   Any ideas?
Jun 08, 2017 1:03:17 AM org.apache.catalina.startup.HostConfig deployDirectory 560 SEVERE: Error deploying web application directory /var/lib/tomcat/webapps/nara 561 java.lang.UnsupportedClassVersionError: org/keycloak/authorization/client/Configuration : Unsupported major.minor version 52.0 562     at java.lang.ClassLoader.defineClass1(Native Method) 563     at java.lang.ClassLoader.defineClass(Unknown Source) 564     at java.security.SecureClassLoader.defineClass(Unknown Source) 565     at java.net.URLClassLoader.defineClass(Unknown Source) 566     at java.net.URLClassLoader.access$100(Unknown Source) 567     at java.net.URLClassLoader$1.run(Unknown Source) 568     at java.net.URLClassLoader$1.run(Unknown Source) 569     at java.security.AccessController.doPrivileged(Native Method) 570     at java.net.URLClassLoader.findClass(Unknown Source) 571     at java.lang.ClassLoader.loadClass(Unknown Source) 572     at java.lang.ClassLoader.loadClass(Unknown Source) 573     at org.keycloak.adapters.authorization.PolicyEnforcer.<init>(PolicyEnforcer.java:55) 574     at org.keycloak.adapters.KeycloakDeploymentBuilder.internalBuild(KeycloakDeploymentBuilder.java     :118) 575     at org.keycloak.adapters.KeycloakDeploymentBuilder.build(KeycloakDeploymentBuilder.java:127) 576     at org.keycloak.adapters.tomcat.AbstractKeycloakAuthenticatorValve.keycloakInit(AbstractKeycloa     kAuthenticatorValve.java:133) 577     at org.keycloak.adapters.tomcat.AbstractKeycloakAuthenticatorValve.lifecycleEvent(AbstractKeycl     oakAuthenticatorValve.java:75) 578     at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) 579     at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90) 580     at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:394) 581     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:165) 582     at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899) 583     at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875) 584     at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652) 585     at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1260) 586     at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:2002) 587     at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) 588     at java.util.concurrent.FutureTask.run(Unknown Source) 589     at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 590     at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 591     at java.lang.Thread.run(Unknown Source)