UnsupportedClassVersionError Deploying webapp in Tomcat 7

Question

I'm deploying a webapp in Tomcat7 which was built by Eclipse using Java Oracle 1.7.

I'm receiving this error which seems to indicate that different Java versions are being used. However when I run java -version I get 'java version "1.7.0_51"' which is the same version as the compilation version.

It should be noted that this web app works fine in the eclipse tomcat server nenvironment, but doesn't seem to work when deploying in the main tomcat installation.

01-May-2014 00:37:46 org.apache.catalina.startup.HostConfig deployWAR INFO: Deploying web application archive /var/lib/tomcat7/webapps/prov.war log4j:WARN No appenders could be found for logger (org.jboss.resteasy.plugins.server.servlet.ConfigurationBootstrap). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. 01-May-2014 00:37:47 org.apache.catalina.core.StandardContext listenerStart SEVERE: Exception sending context initialized event to listener instance of class org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap java.lang.UnsupportedClassVersionError: uk/co/alexjking/prov/ProvClustererWebApp/ClusterHandler : Unsupported major.minor version 51.0 (unable to load class uk.co.alexjking.prov.ProvClustererWebApp.ClusterHandler) at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2840) at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1160) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1668) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1546) at org.jboss.resteasy.plugins.server.servlet.ConfigurationBootstrap.processScannedResources(ConfigurationBootstrap.java:384) at org.jboss.resteasy.plugins.server.servlet.ConfigurationBootstrap.createDeployment(ConfigurationBootstrap.java:181) at org.jboss.resteasy.plugins.server.servlet.ListenerBootstrap.createDeployment(ListenerBootstrap.java:32) at org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap.contextInitialized(ResteasyBootstrap.java:27) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4779) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5273) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:958) at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1599) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1146) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:701) 01-May-2014 00:37:47 org.apache.catalina.core.StandardContext startInternal SEVERE: Error listenerStart 01-May-2014 00:37:47 org.apache.catalina.core.StandardContext startInternal SEVERE: Context [/prov] startup failed due to previous errors 01-May-2014 00:37:47 org.apache.catalina.core.StandardContext listenerStop SEVERE: Exception sending context destroyed event to listener instance of class org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap java.lang.NullPointerException at org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap.contextDestroyed(ResteasyBootstrap.java:37) at org.apache.catalina.core.StandardContext.listenerStop(StandardContext.java:4819) at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5466) at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:160) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:958) at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1599) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1146) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:701)

For completeness, this project has been built using Maven and uses Resteasy.

Answer 1

Your tomcat configuration must be using a different java version. Check catalina.sh / catalina.bat, and check the java version mentioned in those files. By default it uses JAVA_HOME so if you have set it correctly and have not played with tomcat sh/bat files then it should work.