If I click the "Build Now" button on that job, it reports the null pointer exception:

Started by user anonymous
Building remotely on fc-nagios-a in workspace /var/lib/jenkins/mwaite6-slave/workspace/p4-port-linux-Merge
selected Git installation does not exists. Using Default
Fetching changes from the remote Git repository
FATAL: null
java.lang.NullPointerException
at org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession(TrileadSessionFactory.java:34)
at org.eclipse.jgit.transport.SshTransport.getSession(SshTransport.java:121)
at org.eclipse.jgit.transport.TransportGitSsh$SshFetchConnection.<init>(TransportGitSsh.java:248)
at org.eclipse.jgit.transport.TransportGitSsh.openFetch(TransportGitSsh.java:147)
at org.eclipse.jgit.transport.FetchProcess.executeImp(FetchProcess.java:136)
at org.eclipse.jgit.transport.FetchProcess.execute(FetchProcess.java:122)
at org.eclipse.jgit.transport.Transport.fetch(Transport.java:1105)
at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:128)
at org.jenkinsci.plugins.gitclient.JGitAPIImpl.fetch(JGitAPIImpl.java:299)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:275)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:256)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:215)
at hudson.remoting.UserRequest.perform(UserRequest.java:118)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:326)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
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)

When I select "Build Now" on another job, it includes the message in its output:

selected Git installation does not exists. Using Default

That surprises me, since the "JGit" implementation is the only available implementation on my Jenkins server currently, and it is built into Jenkins.

If I then define a Git command line provider in the global configurations and adjust the problem job to use that command line provider, the job works again.

There is a simpler way to show the same (or a similar) stack trace:

• Define a new job using Git as the SCM
• Assign an ssh repository URL like ssh://mwaite@somehost/git/myrepo.git

The stack trace reports a null pointer exception visible in the web browser:

Status Code: 500

Exception: java.lang.NullPointerException
Stacktrace:
javax.servlet.ServletException: java.lang.NullPointerException
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:719)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:770)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:241)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:677)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:770)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:241)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:677)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:770)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:583)
at org.kohsuke.stapler.Stapler.service(Stapler.java:214)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
at winstone.ServletConfiguration.execute(ServletConfiguration.java:248)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:376)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:95)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:87)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:48)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:50)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:331)
at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:227)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.NullPointerException
at org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession(TrileadSessionFactory.java:34)
at org.eclipse.jgit.transport.SshTransport.getSession(SshTransport.java:121)
at org.eclipse.jgit.transport.TransportGitSsh$SshFetchConnection.<init>(TransportGitSsh.java:248)
at org.eclipse.jgit.transport.TransportGitSsh.openFetch(TransportGitSsh.java:147)
at org.jenkinsci.plugins.gitclient.JGitAPIImpl.getHeadRev(JGitAPIImpl.java:313)
at hudson.plugins.git.UserRemoteConfig$DescriptorImpl.doCheckUrl(UserRemoteConfig.java:85)
at sun.reflect.GeneratedMethodAccessor754.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:288)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:151)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:90)
at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:111)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:677)
... 43 more

Generated by Stapler at Thu Aug 01 07:34:06 MDT 2013

mee too with:

• jenkins 1.526
• Jenkins GIT client plugin 1.1.2
• Jenkins GIT plugin 1.4.0

the only solution is revert to 1.0.7

I can't duplicate the problem with Jenkins 1.526, git client plugin 1.1.2, and git plugin 1.4.0. Can you provide more details (like a stack trace)?

I did the following steps as part of my attempt to duplicate the problem:

• install Jenkins 1.509.2
• update to git client plugin 1.1.2 and git plugin 1.4.0
• define a new job "job1" using the git plugin with an ssh URL
• build "job1"
• upgrade to Jenkins 1.526
• define a new job "job2" using the git plugin with an ssh URL
• build "job2"
• build "job1" again

Can you compare my steps with your steps and see if there are any obvious ways we differ?

I was definitely not setting any command line arguments or environment variables to force the use of JGit from within the git 1.4.0 plugin, since my experience with JGit in the 1.4.0 plugin confirmed that it was not ready for production use.

No problem with a newer installation.

I can not use plugin > 1.0.7 in production environment. I have also uninstall and reinstall plugin but nothing. Every old/new job has same problem on build (and polling):
Building on master in workspace /home/builder/.jenkins/jobs/job1/workspace
Checkout:workspace / /home/builder/.jenkins/jobs/job1/workspace - hudson.remoting.LocalChannel@57a3c2bf
Using strategy: Default
Cloning the remote Git repository
[WARNING] JGit doesn't support reference repository. This flag is ignored.
FATAL: null
java.lang.NullPointerException
at org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession(TrileadSessionFactory.java:31)
at org.eclipse.jgit.transport.SshTransport.getSession(SshTransport.java:121)
at org.eclipse.jgit.transport.TransportGitSsh$SshFetchConnection.<init>(TransportGitSsh.java:248)
at org.eclipse.jgit.transport.TransportGitSsh.openFetch(TransportGitSsh.java:147)
at org.eclipse.jgit.transport.FetchProcess.executeImp(FetchProcess.java:136)
at org.eclipse.jgit.transport.FetchProcess.execute(FetchProcess.java:122)
at org.eclipse.jgit.transport.Transport.fetch(Transport.java:1105)
at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:128)
at org.eclipse.jgit.api.CloneCommand.fetch(CloneCommand.java:178)
at org.eclipse.jgit.api.CloneCommand.call(CloneCommand.java:125)
at org.jenkinsci.plugins.gitclient.JGitAPIImpl$3.execute(JGitAPIImpl.java:643)
at org.jenkinsci.plugins.gitclient.AbstractGitAPIImpl.clone(AbstractGitAPIImpl.java:57)
at org.jenkinsci.plugins.gitclient.JGitAPIImpl.clone(JGitAPIImpl.java:98)
at hudson.plugins.git.GitSCM$2.invoke(GitSCM.java:1006)
at hudson.plugins.git.GitSCM$2.invoke(GitSCM.java:942)
at hudson.FilePath.act(FilePath.java:906)
at hudson.FilePath.act(FilePath.java:879)
at hudson.plugins.git.GitSCM.determineRevisionToBuild(GitSCM.java:942)
at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1108)
at org.jenkinsci.plugins.multiplescms.MultiSCM.checkout(MultiSCM.java:117)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1406)
at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:676)
at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:88)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:581)
at hudson.model.Run.execute(Run.java:1597)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:247)

The previous installation was under windows 7.
To debug the problem I do another new installation under Ubuntu 12.10 linux develop machine and I have got the problem.

Debugging in the working case the to org.eclipse.jgit.api.FetchCommand do the normal work, in the second case (not working) a call to org.jenkinsci.plugins.gitclient.trilead.TrileadSessionFactory.getSession was done where the credentialprovider passed from FetchCommand in the firm is null.

The default for git plugin 1.4.0 and git client 1.1.2 is to use the git command line implementation rather than using the jgit implementation (at least as far as I understand it). However, your stack trace shows jgit is being used rather than the git command line implementation. Your stack trace also shows the multiSCM plugin in the stack trace, while the original stack trace does not show that.

You might try disabling or removing the MultiSCM plugin to see if that fixes the issue.

You might also check that there are no settings in your Jenkins startup file which cause it to switch from using the default git command line implementation.