I believe this isn't caused by copyartifact as copyartifact doesn't refer dashboard plugin.
Please report followings:

• Whole Jenkins startup log.
• Complete list of plugins you install to Jenkins.
• From when do you see that error? Did you upgrade Jenkins or any plugins?

Thanks for the reply. I suspected that copyartifact was not the culprit, but it was the plugin I spotted in the backtrace so I mentioned that in the title.

Here is the list of plugins installed and the start of the jenkins log up until the point the exception occurs (if you want even more let me know, but it is quite big)

I am not quite sure when the problem started: I am trying to install the SCM sync plugin and we are having some problems and checking the log I spotted this exception that seems unrelated

Plugins

all-changes 1.3 false false
analysis-core 1.69 true false
ant 1.2 true true
antisamy-markup-formatter 1.3 true true
changes-since-last-success 0.5 true false
checkstyle 3.41 true false
cobertura 1.9.6 true false
conditional-buildstep 1.3.3 true false
config-file-provider 2.7.5 true false
copy-to-slave 1.4.3 true false
copyartifact 1.34 true false
credentials 1.22 true true
custom-job-icon 0.2 true false
custom-tools-plugin 0.4.4 true false
cvs 2.12 false true
depgraph-view 0.11 true false
description-setter 1.9 true false
downstream-buildview 1.9 true false
email-ext 2.39 true false
envfile 1.2 true false
extended-choice-parameter 0.34 true false
external-monitor-job 1.4 true false
favorite 1.16 true false
findbugs 4.59 true false
git 2.3.4 true false
git-client 1.16.1 true false
gravatar 2.1 true false
greenballs 1.14 false false
htmlpublisher 1.3 true false
ivy 1.24 true false
jacoco 1.0.18 true false
javadoc 1.3 true true
jenkins-tag-cloud-plugin 1.6 true false
jquery 1.7.2-1 true false
jquery-ui 1.0.2 true false
junit 1.4 true true
ldap 1.11 true true
mailer 1.15 true true
mapdb-api 1.0.6.0 true false
matrix-auth 1.2 true true
matrix-project 1.4 true true
maven-plugin 2.8 true true
memegen 0.4.3 true false
multiple-scms 0.3 true false
next-build-number 1.1 true false
nodelabelparameter 1.5.1 true false
pam-auth 1.2 true true
parameterized-trigger 2.25 true false
pending-changes 0.3.0 true false
pmd 3.40 true false
promoted-builds 2.19 true false
publish-over-cifs 0.3 true false
publish-over-ftp 1.11 true false
publish-over-ssh 1.12 true false
release 2.4.1 true false
run-condition 1.0 true false
saferestart 0.3 true false
scm-api 0.2 true false
scm-sync-configuration 0.0.8 true false
scp 1.8 true false
script-security 1.13 true false
setenv 1.1 true false
shelve-project-plugin 1.5 true false
slave-status 1.6 true false
sloccount 1.20 true false
ssh 2.4 true false
ssh-agent 1.5 true false
ssh-credentials 1.10 true true
ssh-slaves 1.9 true true
subversion 2.5 true true
svn-release-mgr 1.2 true false
svn-tag 1.17 true false
svnpublisher 0.1 true false
template-project 1.4.2 true false
throttle-concurrents 1.8.4 true false
token-macro 1.10 true false
translation 1.12 true true
URLSCM 1.6 true false
viewVC 1.7 true false
violations 0.7.11 true false
warnings 4.45 true false
windows-slaves 1.0 true false
ws-cleanup 0.25 true false
xshell 0.10 true false

Feb 12, 2015 10:37:06 AM INFO winstone.Logger logInternal
Winstone Servlet Engine v2.0 running: controlPort=disabled
Feb 12, 2015 10:37:07 AM INFO jenkins.InitReactorRunner$1 onAttained
Started initialization
Feb 12, 2015 10:37:07 AM INFO hudson.ClassicPluginStrategy createPluginWrapper
Plugin greenballs.jpi is disabled
Feb 12, 2015 10:37:07 AM INFO hudson.ClassicPluginStrategy createPluginWrapper
Plugin cvs.jpi is disabled
Feb 12, 2015 10:37:09 AM INFO hudson.ClassicPluginStrategy createPluginWrapper
Plugin all-changes.jpi is disabled
Feb 12, 2015 10:37:09 AM INFO jenkins.InitReactorRunner$1 onAttained
Listed all plugins
Feb 12, 2015 10:37:15 AM INFO hudson.plugins.memegen.PluginImpl start
starting memegen plugin
Feb 12, 2015 10:37:18 AM INFO com.youdevise.hudson.slavestatus.SlaveListenerInitiator init
Initialising slave-status plugin
Feb 12, 2015 10:37:18 AM INFO jenkins.InitReactorRunner$1 onAttained
Prepared all plugins
Feb 12, 2015 10:37:22 AM WARNING hudson.ExtensionFinder$GuiceFinder$SezpozModule configure
Failed to load hudson.plugins.release.dashboard.RecentReleasesPortlet$DescriptorImpl
java.lang.LinkageError: Failed to resolve class hudson.plugins.release.dashboard.RecentReleasesPortlet$DescriptorImpl
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:491)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.configure(ExtensionFinder.java:524)
at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:253)
at com.google.inject.spi.Elements.getElements(Elements.java:108)
at com.google.inject.internal.InjectorShell$Builder.build(InjectorShell.java:135)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:104)
at com.google.inject.Guice.createInjector(Guice.java:96)
at com.google.inject.Guice.createInjector(Guice.java:73)
at hudson.ExtensionFinder$GuiceFinder.<init>(ExtensionFinder.java:279)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at java.lang.Class.newInstance(Class.java:379)
at net.java.sezpoz.IndexItem.instance(IndexItem.java:181)
at hudson.ExtensionFinder$Sezpoz._find(ExtensionFinder.java:642)
at hudson.ExtensionFinder$Sezpoz.find(ExtensionFinder.java:617)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:371)
at hudson.ExtensionList.load(ExtensionList.java:300)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:253)
at hudson.ExtensionList.iterator(ExtensionList.java:143)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:364)
at hudson.ExtensionList.load(ExtensionList.java:300)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:253)
at hudson.ExtensionList.iterator(ExtensionList.java:143)
at jenkins.model.Jenkins.getDescriptorByType(Jenkins.java:1191)
at hudson.plugins.copyartifact.BuildSelectorParameter.initAliases(BuildSelectorParameter.java:99)
at hudson.plugins.copyartifact.CopyArtifactPlugin.postInitialize(CopyArtifactPlugin.java:35)
at hudson.PluginManager$2$1$2.run(PluginManager.java:386)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:903)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.TypeNotPresentException: Type hudson.plugins.view.dashboard.DashboardPortlet not present
at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:117)
at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:125)
at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
at sun.reflect.generics.visitor.Reifier.reifyTypeArguments(Reifier.java:68)
at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:138)
at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
at sun.reflect.generics.repository.ClassRepository.getSuperclass(ClassRepository.java:84)
at java.lang.Class.getGenericSuperclass(Class.java:701)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:476)
... 37 more
Caused by: java.lang.ClassNotFoundException: hudson.plugins.view.dashboard.DashboardPortlet
at jenkins.util.AntClassLoader.findClassInComponents(AntClassLoader.java:1375)
at jenkins.util.AntClassLoader.findClass(AntClassLoader.java:1325)
at jenkins.util.AntClassLoader.loadClass(AntClassLoader.java:1078)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:274)
at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:114)
... 45 more

Feb 12, 2015 10:37:31 AM INFO jenkins.InitReactorRunner$1 onAttained
Started all plugins
Feb 12, 2015 10:37:32 AM INFO jenkins.InitReactorRunner$1 onAttained
Augmented all extensions
Feb 12, 2015 10:37:33 AM INFO hudson.plugins.scm_sync_configuration.ScmSyncConfigurationBusiness queueChangeSet
Queue of changeset A hudson.model.UpdateCenter.xml
aborted (scm manipulator not settled !)
Feb 12, 2015 10:37:33 AM INFO hudson.plugins.copyartifact.CopyArtifact setUpgradeNeeded
Upgrade for Copy Artifact is scheduled.
Feb 12, 2015 10:37:44 AM INFO jenkins.InitReactorRunner$1 onAttained
Loaded all jobs
Feb 12, 2015 10:37:44 AM WARNING hudson.plugins.copyartifact.CopyArtifact upgradeCopyArtifact
Update of CopyArtifact is scheduled, but no CopyArtifact to upgrade was found!
Feb 12, 2015 10:37:45 AM INFO org.jenkinsci.main.modules.sshd.SSHD start
Started SSHD at port 58125
Feb 12, 2015 10:37:45 AM INFO jenkins.InitReactorRunner$1 onAttained
Completed initialization
Feb 12, 2015 10:37:47 AM INFO org.springframework.web.context.support.StaticWebApplicationContext prepareRefresh
Refreshing org.springframework.web.context.support.StaticWebApplicationContext@501ff9c: display name [Root WebApplicationContext]; startup date [Thu Feb 12 10:37:47 CET 2015]; root of context hierarchy
Feb 12, 2015 10:37:47 AM INFO org.springframework.web.context.support.StaticWebApplicationContext obtainFreshBeanFactory
Bean factory for application context [org.springframework.web.context.support.StaticWebApplicationContext@501ff9c]: org.springframework.beans.factory.support.DefaultListableBeanFactory@7c20ada9
Feb 12, 2015 10:37:47 AM INFO org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@7c20ada9: defining beans [initialDirContextFactory,bindAuthenticator,ldapUserSearch,authenticationManager,authoritiesPopulator]; root of factory hierarchy
Feb 12, 2015 10:37:47 AM INFO org.acegisecurity.ldap.DefaultInitialDirContextFactory setProviderUrl
URL 'ldap://172.16.10.23:389/ou=People,dc=nice', root DN is 'ou=People,dc=nice'
Feb 12, 2015 10:37:47 AM INFO org.acegisecurity.ldap.search.FilterBasedLdapUserSearch
SearchBase not set. Searches will be performed from the root: ou=People,dc=nice
Feb 12, 2015 10:37:47 AM INFO org.acegisecurity.providers.ldap.populator.DefaultLdapAuthoritiesPopulator setGroupSearchBase
groupSearchBase is empty. Searches will be performed from the root: ou=People,dc=nice
Feb 12, 2015 10:37:47 AM INFO org.springframework.web.context.support.StaticWebApplicationContext prepareRefresh
Refreshing org.springframework.web.context.support.StaticWebApplicationContext@7d342f07: display name [Root WebApplicationContext]; startup date [Thu Feb 12 10:37:47 CET 2015]; root of context hierarchy
Feb 12, 2015 10:37:47 AM INFO org.springframework.web.context.support.StaticWebApplicationContext obtainFreshBeanFactory
Bean factory for application context [org.springframework.web.context.support.StaticWebApplicationContext@7d342f07]: org.springframework.beans.factory.support.DefaultListableBeanFactory@6898a972
Feb 12, 2015 10:37:47 AM INFO org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@6898a972: defining beans [filter,legacy]; root of factory hierarchy
Feb 12, 2015 10:37:48 AM INFO hudson.slaves.SlaveComputer tryReconnect
Attempting to reconnect hudson-ef
Feb 12, 2015 10:37:48 AM INFO hudson.slaves.SlaveComputer tryReconnect
Attempting to reconnect macbook
Feb 12, 2015 10:37:48 AM INFO hudson.slaves.SlaveComputer tryReconnect
Attempting to reconnect hudson-centos6-physical
Feb 12, 2015 10:37:48 AM INFO com.youdevise.hudson.slavestatus.SlaveListenerInitiator onOnline
Starting slave-status listener on
Feb 12, 2015 10:37:48 AM INFO com.youdevise.hudson.slavestatus.SlaveListener call
Slave-status listener starting
Feb 12, 2015 10:37:48 AM INFO com.youdevise.hudson.slavestatus.SocketHTTPListener waitForConnection
Slave-status listener ready on port 3141

Looks more like something may have gone wrong extracting dashboard view. I'd try trashing the folders in JENKINS_HOME/plugins/ while Jenkins is stopped to have it recreate them from jpi's upon next start.

That looks caused by release-plugin.
Uninstalling release-plugin or installing dashboard-view plugin should resolve the problem.

I confirm the execption goes away if I remove the release-plugin

+1

https://github.com/jenkinsci/release-plugin/blob/cf22988f0beefd642daa37a5bcf14d463f607aab/src/main/java/hudson/plugins/release/dashboard/RecentReleasesPortlet.java#L123

https://github.com/jenkinsci/release-plugin/blob/cf22988f0beefd642daa37a5bcf14d463f607aab/pom.xml#L78

No idea why the weird hack in newInstance when Extension(optional = true) would handle it…

Code changed in jenkins
User: Adrien Lecharpentier
Path:
src/main/java/hudson/plugins/release/dashboard/RecentReleasesPortlet.java
http://jenkins-ci.org/commit/release-plugin/fbf239c96b7baf9a7cc609397bd03077028fcc41
Log:
JENKINS-26895 Fix optional dependency check on dashboard-view

Code changed in jenkins
User: Oleg Nenashev
Path:
src/main/java/hudson/plugins/release/dashboard/RecentReleasesPortlet.java
http://jenkins-ci.org/commit/release-plugin/a11d6a9895431d43a1fed8794d9aac1ccad70670
Log:
Merge pull request #28 from alecharp/JENKINS-26895

JENKINS-26895 Fix optional dependency check on dashboard-view

Compare: https://github.com/jenkinsci/release-plugin/compare/cf22988f0bee...a11d6a989543

alecharp has proposed a fix for this issue.
It has been released in Release Plugin 2.9