Connecting to ZK on SSL port (secureClient: ClassNotDef found error)

 I managed to setup Zookeeper 3.5.5 with secure Client enabled and configured in solr.in.sh the zookeeper properties to use that port, which offers SSL.

However, I see the following error in the logfiles when starting up Solr:

2019-07-30 14:59:09.704 INFO  (main) [   ] o.a.z.c.X509Util Setting -D jdk.tls.rejectClientInitiatedRenegotiation=true to disable client-initiated TLS renegotiation
2019-07-30 14:59:09.710 ERROR (main) [   ] o.a.s.s.SolrDispatchFilter Could not start Solr. Check solr/home property and the logs
2019-07-30 14:59:09.743 ERROR (main) [   ] o.a.s.c.SolrCore null:java.lang.NoClassDefFoundError: io/netty/channel/ChannelHandler
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:315)
    at org.apache.zookeeper.ZooKeeper.getClientCnxnSocket(ZooKeeper.java:3063)
    at org.apache.zookeeper.ZooKeeper.<init>(ZooKeeper.java:883)
    at org.apache.zookeeper.ZooKeeper.<init>(ZooKeeper.java:801)
    at org.apache.zookeeper.ZooKeeper.<init>(ZooKeeper.java:950)
    at org.apache.zookeeper.ZooKeeper.<init>(ZooKeeper.java:688)
    at org.apache.solr.common.cloud.SolrZooKeeper.<init>(SolrZooKeeper.java:43)
    at org.apache.solr.common.cloud.ZkClientConnectionStrategy.createSolrZooKeeper(ZkClientConnectionStrategy.java:105)
    at org.apache.solr.common.cloud.DefaultConnectionStrategy.connect(DefaultConnectionStrategy.java:37)
    at org.apache.solr.common.cloud.SolrZkClient.<init>(SolrZkClient.java:166)
    at org.apache.solr.common.cloud.SolrZkClient.<init>(SolrZkClient.java:125)
    at org.apache.solr.common.cloud.SolrZkClient.<init>(SolrZkClient.java:120)
    at org.apache.solr.common.cloud.SolrZkClient.<init>(SolrZkClient.java:107)
    at org.apache.solr.servlet.SolrDispatchFilter.loadNodeConfig(SolrDispatchFilter.java:282)
    at org.apache.solr.servlet.SolrDispatchFilter.createCoreContainer(SolrDispatchFilter.java:259)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:181)
    at org.eclipse.jetty.servlet.FilterHolder.initialize(FilterHolder.java:136)
    at org.eclipse.jetty.servlet.ServletHandler.lambda$initialize$0(ServletHandler.java:750)
    at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
    at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:744)
    at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:369)
    at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1497)
    at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1459)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:854)
    at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:278)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:545)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:46)
    at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:192)
    at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:510)
    at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:153)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:172)
    at org.eclipse.jetty.deploy.providers.WebAppProvider.fileAdded(WebAppProvider.java:436)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:65)
    at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:610)
    at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:529)
    at org.eclipse.jetty.util.Scanner.scan(Scanner.java:392)
    at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:313)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:145)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:598)
    at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:240)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:167)
    at org.eclipse.jetty.server.Server.start(Server.java:418)
    at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:119)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:113)
    at org.eclipse.jetty.server.Server.doStart(Server.java:382)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
    at org.eclipse.jetty.xml.XmlConfiguration.lambda$main$0(XmlConfiguration.java:1797)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1746)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.eclipse.jetty.start.Main.invokeMain(Main.java:220)
    at org.eclipse.jetty.start.Main.start(Main.java:490)
    at org.eclipse.jetty.start.Main.main(Main.java:77)
Caused by: java.lang.ClassNotFoundException: io.netty.channel.ChannelHandler
    at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:555)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 64 more

Is there a jar file missing in the Solr distribution? Can this be fixed by copying the Jar file in 8.2 to the webapp/lib directory?