HTTP ERROR 500

Problem accessing /solr/admin. Reason:

    {msg=SolrCore 'ezp-default' is not available due to init failure: org/ezsystems/solr/handler/ezfind/eZFindRequestHandler : Unsupported major.minor version 51.0,trace=org.apache.solr.common.SolrException: SolrCore 'ezp-default' is not available due to init failure: org/ezsystems/solr/handler/ezfind/eZFindRequestHandler : Unsupported major.minor version 51.0
	at org.apache.solr.core.CoreContainer.getCore(CoreContainer.java:827)
	at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:317)
	at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:217)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1419)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
	at org.eclipse.jetty.server.Server.handle(Server.java:368)
	at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
	at org.eclipse.jetty.server.BlockingHttpConnection.handleRequest(BlockingHttpConnection.java:53)
	at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:942)
	at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1004)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:640)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
	at org.eclipse.jetty.server.BlockingHttpConnection.handle(BlockingHttpConnection.java:72)
	at org.eclipse.jetty.server.bio.SocketConnector$ConnectorEndPoint.run(SocketConnector.java:264)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
	at java.lang.Thread.run(Thread.java:701)
Caused by: org.apache.solr.common.SolrException: org/ezsystems/solr/handler/ezfind/eZFindRequestHandler : Unsupported major.minor version 51.0
	at org.apache.solr.core.SolrCore.<init>(SolrCore.java:844)
	at org.apache.solr.core.SolrCore.<init>(SolrCore.java:630)
	at org.apache.solr.core.CoreContainer.createFromLocal(CoreContainer.java:562)
	at org.apache.solr.core.CoreContainer.create(CoreContainer.java:597)
	at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:258)
	at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:250)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
	at java.util.concurrent.FutureTask.run(FutureTask.java:166)
	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)
	... 1 more
Caused by: java.lang.UnsupportedClassVersionError: org/ezsystems/solr/handler/ezfind/eZFindRequestHandler : Unsupported major.minor version 51.0
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:643)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
	at java.net.FactoryURLClassLoader.loadClass(URLClassLoader.java:615)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:316)
	at java.net.FactoryURLClassLoader.loadClass(URLClassLoader.java:615)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:270)
	at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:454)
	at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:401)
	at org.apache.solr.core.SolrCore.createInstance(SolrCore.java:531)
	at org.apache.solr.core.SolrCore.createRequestHandler(SolrCore.java:604)
	at org.apache.solr.core.RequestHandlers.initHandlersFromConfig(RequestHandlers.java:153)
	at org.apache.solr.core.SolrCore.<init>(SolrCore.java:774)
	... 13 more
,code=500}