Hi,

We encountered the following issue while we trying to upgrade our current jenkins 2.7.3 to the latest one available in market 2.125 version.

Java version currently we using 

openjdk version "1.8.0_121"
OpenJDK Runtime Environment (build 1.8.0_121-b13)
OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)

java.lang.NullPointerException
at smartjenkins.SmartJenkinsComputerListener.onConfigurationChange(SmartJenkinsComputerListener.java:41)
at hudson.model.AbstractCIBase.updateComputerList(AbstractCIBase.java:231)
at jenkins.model.Jenkins.updateComputerList(Jenkins.java:1551)
at jenkins.model.Nodes$9.run(Nodes.java:348)
at hudson.model.Queue._withLock(Queue.java:1378)
at hudson.model.Queue.withLock(Queue.java:1255)
at jenkins.model.Nodes.load(Nodes.java:339)
at jenkins.model.Jenkins$14.run(Jenkins.java:3110)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:296)
at jenkins.model.Jenkins$5.runTask(Jenkins.java:1068)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:214)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused: org.jvnet.hudson.reactor.ReactorException
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:282)
at jenkins.InitReactorRunner.run(InitReactorRunner.java:48)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:1102)
at jenkins.model.Jenkins.<init>(Jenkins.java:904)
at hudson.model.Hudson.<init>(Hudson.java:85)
at hudson.model.Hudson.<init>(Hudson.java:81)
at hudson.WebAppMain$3.run(WebAppMain.java:233)
Caused: hudson.util.HudsonFailedToLoad
at hudson.WebAppMain$3.run(WebAppMain.java:250)

Any help that you provide is greatly appreciated.