I get the following exception when accessing the Cloud -> ZK Status page in Solr 8.6.0:
ERROR [20200721T080439,063] qtp478489615-24 org.apache.solr.servlet.HttpSolrCall - null:java.lang.NumberFormatException: null at java.base/java.lang.Integer.parseInt(Integer.java:620) at java.base/java.lang.Integer.parseInt(Integer.java:776) at org.apache.solr.common.cloud.ZkDynamicConfig$Server.parseLine(ZkDynamicConfig.java:142) at org.apache.solr.common.cloud.ZkDynamicConfig.lambda$parseLines$0(ZkDynamicConfig.java:58) at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133) at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801) at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658) at org.apache.solr.common.cloud.ZkDynamicConfig.parseLines(ZkDynamicConfig.java:53) at org.apache.solr.handler.admin.ZookeeperStatusHandler.handleRequestBody(ZookeeperStatusHandler.java:83) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:214) at org.apache.solr.servlet.HttpSolrCall.handleAdmin(HttpSolrCall.java:854) at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:818) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:566) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:415) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:345) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1596) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:590) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1610) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1300) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1580) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1215) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.Server.handle(Server.java:500) at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383) at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:375) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806) at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938) at java.base/java.lang.Thread.run(Thread.java:830) My zknode's /zookeeper/config has this content: server.1=dev-confluentzoo2014.sol-osl01.host.example.com:7795:7796:participant server.2=dev-confluentzoo2015.sol-osl01.host.example.com:7795:7796:participant server.3=dev-confluentzoo2016.sol-osl01.host.example.com:7795:7796:participant version=0 This problem does not occur in 8.5.x. Cheers, Henrik