Error reported on start page with the following stack trace:

org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:246)
at jenkins.InitReactorRunner.run(InitReactorRunner.java:43)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:811)
at jenkins.model.Jenkins.<init>(Jenkins.java:732)
at hudson.model.Hudson.<init>(Hudson.java:81)
at hudson.model.Hudson.<init>(Hudson.java:77)
at hudson.WebAppMain$2.run(WebAppMain.java:217)
Caused by: java.lang.Error: java.lang.reflect.InvocationTargetException
at hudson.init.InitializerFinder.invoke(InitializerFinder.java:124)
at hudson.init.InitializerFinder$TaskImpl.run(InitializerFinder.java:184)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
at jenkins.model.Jenkins$5.runTask(Jenkins.java:800)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:897)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:919)
at java.lang.Thread.run(Thread.java:736)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:60)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
at java.lang.reflect.Method.invoke(Method.java:611)
at hudson.init.InitializerFinder.invoke(InitializerFinder.java:120)
... 8 more
Caused by: java.lang.NullPointerException
at org.jenkinsci.main.modules.sshd.SSHD.init(SSHD.java:133)
... 13 more

Jenkins not usable.

The bug may be related to https://issues.jenkins-ci.org/browse/JENKINS-12338 with a similar stack trace. However, Jenkins is started stand-alone in that issue. A common fact is that both use the IBM J9 JDK. Maybe a JDK incompatibility?

Several other stacktraces in SystemOut.log of Websphere (see attachment).