I do not reproduce the issue using Jenkins 1.568.
Which version of the monitoring plugin do you use?

It was probably 1.50.0, I had to remove it to be able to work. But please resolve case if you can not reproduce with current Jenkins version and latest plugin version.

OK, so I resolve as can not reproduce. Please reopen if you reproduce.

My test was with monitoring plugin v1.51 and Jenkins 1.568.
I think that your issue was something "temporary", since many users probably have the same versions as you.

Same issue. Only thing I can think of - our Jenkins uses JDK8.

Hi magnayn.

Try stopping the Jenkins service, then cd into ${JENKINS_HOME}/plugins and remove the file monitoring.jpi as well as monitoring directory.
Then start Jenkins, and reinstall monitoring plugin.
Report back your findings, then evernat get's something to work with. If you can send him your Jenkins log, it may be usefull too.

Reproduced on Ubuntu 14.04, Jenkins 1.574 + latest monitoring plugin
After installing the monitoring plugin, Jenkins does not complete startup as described above.
Removing the plugin fixes.
I use Oracle java version 1.7.0_65-b17

Can this be reproduced with Jenkins out of the box, only installing this plugin? I can't on CentOS, but maybe you can?

If not, would be interesting if anyone experiencing this could provide a full list of plugins installed. (Go to /systemInfo and scroll down.)

These are my installed plugins:
saferestart Safe Restart Plugin 0.3
description-setter description setter plugin 1.9
jquery jQuery plugin 1.7.2-1
analysis-core Static Analysis Utilities 1.57
javadoc Javadoc Plugin 1.2
htmlpublisher HTML Publisher plugin 1.3
xunit xUnit plugin 1.90
pam-auth PAM Authentication plugin 1.1
warnings Warnings Plug-in 4.40
parameterized-trigger Parameterized Trigger plugin 2.25
ci-game Continuous Integration game 1.20
clover Clover plugin 4.4.0
antisamy-markup-formatter OWASP Markup Formatter Plugin 1.2
ant Ant Plugin 1.2
matrix-auth Matrix Authorization Strategy Plugin 1.2
jobConfigHistory Job Configuration History Plugin 2.8
github GitHub plugin 1.9.1
subversion Subversion Plug-in 2.4.1
token-macro Token Macro Plugin 1.10
external-monitor-job External Monitor Job Type Plugin 1.2
ws-cleanup Workspace Cleanup Plugin 0.22
matrix-project Matrix Project Plugin 1.3
cvs CVS Plug-in 2.12
covcomplplot Coverage/Complexity Scatter Plot PlugIn 1.1.1
disk-usage disk-usage plugin 0.24
log-parser Log Parser Plugin 1.0.8
git-client GIT client plugin 1.10.1
scm-api SCM API Plugin 0.2
build-keeper-plugin Build Keeper Plugin 1.3
checkstyle Checkstyle Plug-in 3.39
text-finder TextFinder plugin 1.10
windows-slaves Windows Slaves Plugin 1.0
maven-plugin Maven Integration plugin 2.6
ssh-credentials SSH Credentials Plugin 1.8
nodelabelparameter Node and Label parameter plugin 1.5.1
mapdb-api MapDB API Plugin 1.0.1.0
git GIT plugin 2.2.4
github-api GitHub API Plugin 1.56
ssh-agent SSH Agent Plugin 1.5
jsunit JSUnit plugin 1.5
logging Logging Plugin 0.2.8
ghprb GitHub Pull Request Builder 1.14
tasks Task Scanner Plug-in 4.39
ssh-slaves SSH Slaves plugin 1.6
ansicolor AnsiColor 0.4.0
multiple-scms Multiple SCMs plugin 0.3
violations Violations plugin 0.7.11
ircbot IRC Plugin 2.25
ldap LDAP Plugin 1.10.2
run-condition Run Condition Plugin 1.0
translation Translation Assistance plugin 1.11
ssh SSH plugin 2.4
instant-messaging instant-messaging plugin 1.29
jslint Box UK - JSLint 0.8.2
credentials Credentials Plugin 1.16.1
violation-columns Violation Columns(List View Columns) 1.6
mailer Mailer Plugin 1.10
Parameterized-Remote-Trigger Parameterized Remote Trigger Plugin 2.1.3

Does this issue still occur?

Is Jenkins running standalone or in a container?

Which Java version, OS, Jenkins version, Monitoring plugin, specifically?

Does the same issue occur on the same OS, Java version when run standalone on a new Jenkins home directory, with only Monitoring plugin installed?

I've hit this. Jenkins version 1.596.2. Nuking the monitoring plugin lets jenkins start up.

If I then attempt to install the monitoring plugin (1.55.0) from the plugin manager with "Download now and install after restart", Jenkins will never start back up after restart. This is what my startup log looks like:

Running from: /opt/jenkins-war/jenkins-1.596.2.war
webroot: System.getProperty("JENKINS_HOME")
Apr 10, 2015 11:33:13 AM winstone.Logger logInternal
INFO: Beginning extraction from war file
Apr 10, 2015 11:33:14 AM org.eclipse.jetty.util.log.JavaUtilLog info
INFO: jetty-winstone-2.8

Apr 10, 2015 11:33:15 AM org.eclipse.jetty.util.log.JavaUtilLog info
INFO: NO JSP Support for , did not find org.apache.jasper.servlet.JspServlet

Jenkins home directory: /space/jenkins_instances/support found at: System.getProperty("JENKINS_HOME")
Apr 10, 2015 11:33:16 AM org.eclipse.jetty.util.log.JavaUtilLog info
INFO: Started SelectChannelConnector@0.0.0.0:18007
Apr 10, 2015 11:33:16 AM org.eclipse.jetty.util.log.JavaUtilLog info
INFO: Started Ajp13SocketConnector@0.0.0.0:19007
Apr 10, 2015 11:33:16 AM org.eclipse.jetty.util.log.JavaUtilLog info
INFO: AJP13 is not a secure protocol. Please protect port 19007
Apr 10, 2015 11:33:16 AM winstone.Logger logInternal
INFO: Winstone Servlet Engine v2.0 running: controlPort=disabled
Apr 10, 2015 11:33:17 AM jenkins.InitReactorRunner$1 onAttained
INFO: Started initialization
Apr 10, 2015 11:33:17 AM jenkins.InitReactorRunner$1 onAttained
INFO: Listed all plugins
Apr 10, 2015 11:33:18 AM org.jvnet.hudson.plugins.m2release.M2ReleaseBuildWrapper$DescriptorImpl <clinit>
INFO: Using new style Permission with PermissionScope
Apr 10, 2015 11:33:18 AM de.pellepelster.jenkins.walldisplay.WallDisplayPlugin loadConfiguration
INFO: Loaded configuration data: de.pellepelster.jenkins.walldisplay.Configuration@4b22b775[
  theme=default
  jenkinsTimeOut=15
  jenkinsUpdateInterval=20
  showDetails=false
  showGravatar=false
  fontFamily=sans-serif
  buildRange=all
  sortOrder=job name
  showWeatherReport=<null>
  showJunitResults=<null>
  maxQueuePositionToShow=0
  gravatarUrl=<null>
]
log4j:WARN No appenders could be found for logger (net.bull.javamelody).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "pool-5-thread-1" java.lang.ClassCircularityError: java/util/logging/LogRecord
        at net.bull.javamelody.LoggingHandler.publish(LoggingHandler.java:109)
        at java.util.logging.Logger.log(Logger.java:610)
        at java.util.logging.Logger.doLog(Logger.java:631)
        at java.util.logging.Logger.log(Logger.java:720)
        at jenkins.InitReactorRunner$1.onTaskFailed(InitReactorRunner.java:71)
        at org.jvnet.hudson.reactor.ReactorListener$Aggregator.onTaskFailed(ReactorListener.java:99)
        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:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:724)
Apr 10, 2015 11:33:40 AM org.eclipse.jetty.util.log.JavaUtilLog warn
WARNING: /static/0c6a5c26/scripts/prototype.js
java.lang.ClassCircularityError: java/util/logging/LogRecord
        at net.bull.javamelody.LoggingHandler.publish(LoggingHandler.java:109)
[...]

By comparison, a successful startup (after removing the plugin again) shows

[...]
Apr 10, 2015 11:36:14 AM de.pellepelster.jenkins.walldisplay.WallDisplayPlugin loadConfiguration
INFO: Loaded configuration data: de.pellepelster.jenkins.walldisplay.Configuration@5ae856b5[
  theme=default
  jenkinsTimeOut=15
  jenkinsUpdateInterval=20
  showDetails=false
  showGravatar=false
  fontFamily=sans-serif
  buildRange=all
  sortOrder=job name
  showWeatherReport=<null>
  showJunitResults=<null>
  maxQueuePositionToShow=0
  gravatarUrl=<null>
]
Apr 10, 2015 11:36:14 AM jenkins.InitReactorRunner$1 onAttained
INFO: Prepared all plugins
[...]

Oracle java version 1.7.0_25. For reference, I'm managing about 45 jenkins instances, all on the same machine and JDK version (with assorted different jenkins version/plugin lists). I'm only having this issue with one of them.

aidanhs Please provide all the information I asked for last year.

Can this be reproduced with Jenkins out of the box, only installing this plugin? I can't on CentOS, but maybe you can?

If not, would be interesting if anyone experiencing this could provide a full list of plugins installed. (Go to /systemInfo and scroll down.)

Is Jenkins running standalone or in a container?

Which Java version, OS, Jenkins version, Monitoring plugin, specifically?

Does the same issue occur on the same OS, Java version when run standalone on a new Jenkins home directory, with only Monitoring plugin installed?

In your specific case it would be helpful if you mentioned what's different about that one machine from all the other ones.

Without preventing you to give info, it can be noted that the monitoring plugin currently bundles the slf4j-api:
https://github.com/jenkinsci/monitoring-plugin/blob/master/pom.xml#L49

Sl4j-api is in theory not related to java.util.logging, but I can build a specific version without that if you want to make a test.
(Or you can remove WEB-INF/lib/slf4j-api-1.6.3.jar by yourself from the monitoring.hpi file with a zip manager and then uninstall / reinstall.)

Maybe this has a similar cause as JENKINS-27669?

I have the same issue.

Jenkins 1.596.2

As said above, the monitoring plugin currently bundles the slf4j-api.
Can you try a new build of the monitoring plugin without the slf4j-api?

monitoring.hpi is attached and is the same as v1.56 except slf4j-api.
You can install it in your Jenkins with Manage Jenkins / Manage plugins / Advanced / Upload plugin.

I tried the attached monitoring.hpi file with Jenkins 1.618. Unfortunately the problem and the exception remains.

Problem is still occurring.

After reading JENKINS-27669, perhaps it is needed to preload the java.util.logging.LogRecord class, before net.bull.javamelody.LoggingHandler.publish(...) is called.

@jbrejner A possible cause triggering the issue for you may be that you have also the "Logging plugin" installed.

Code changed in jenkins
User: evernat
Path:
src/main/java/org/jvnet/hudson/plugins/monitoring/PluginImpl.java
http://jenkins-ci.org/commit/monitoring-plugin/0ad60da0038048ca69672022e54434cb3c5c87a3
Log:
try to fix JENKINS-23442 (ClassCircularityError: java/util/logging/LogRecord)

So now resolved/fixed?

The code changed in the plugin is a tentative fix without having reproduced the issue myself.
So, I would like a confirmation from a user before saying that it is fixed.

To everyone:
You can test the fix by downloading a nightly build here:
https://javamelody.ci.cloudbees.com/job/jenkins%20plugin/ws/target/monitoring.hpi

It seems to be working for us, we had the same problem before. And now, after installing the snapshot it doesn't hang anymore (and we can acess /monitoring)

Thanks Anders for the confirmation.