Steps to reproduce error:

Install logstash plugin. Go to configure job page, under "Build Environments" options, choose 'send console log to Logstash' and save the job. Exception is thrown.

(FYI, the 'send console log to Logstash'  option as a 'post build action" works fine.)

Exception:

A problem occurred while processing the request. Please check our bug tracker to see if a similar problem has already been reported. If it is already reported, please vote and put a comment on it to let us gauge the impact of the problem. If you think this is a new issue, please file a new issue. When you file an issue, make sure to add the entire stack trace, along with the version of Jenkins and relevant plugins. The users list might be also useful in understanding what has happened.

Stack trace

java.lang.ClassNotFoundException: com.michelin.cio.hudson.plugins.maskpasswords.MaskPasswordsOutputStream at jenkins.util.AntClassLoader.findClassInComponents(AntClassLoader.java:1374) at jenkins.util.AntClassLoader.findClass(AntClassLoader.java:1327) at jenkins.util.AntClassLoader.loadClass(AntClassLoader.java:1080) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) Caused: java.lang.NoClassDefFoundError: com/michelin/cio/hudson/plugins/maskpasswords/MaskPasswordsOutputStream at java.lang.Class.getDeclaredFields0(Native Method) at java.lang.Class.privateGetDeclaredFields(Class.java:2583) at java.lang.Class.privateGetPublicFields(Class.java:2614) at java.lang.Class.getFields(Class.java:1557) at org.kohsuke.stapler.ClassDescriptor.<init>(ClassDescriptor.java:80) at org.kohsuke.stapler.RequestImpl.instantiate(RequestImpl.java:764) at org.kohsuke.stapler.RequestImpl.access$200(RequestImpl.java:83) at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:678) at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:478) at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:474) at hudson.model.Descriptor.newInstance(Descriptor.java:592) at hudson.util.DescribableList.rebuild(DescribableList.java:177) at hudson.model.Project.submit(Project.java:229) at hudson.model.Job.doConfigSubmit(Job.java:1315) at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:771) at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627) at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:343) at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:52) at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26) at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:184) at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:117) at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:129) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715) Caused: javax.servlet.ServletException at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:765) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845) at org.kohsuke.stapler.MetaClass$5.doDispatch(MetaClass.java:248) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649) at org.kohsuke.stapler.Stapler.service(Stapler.java:238) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:841) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135) at org.jenkinsci.plugins.corsfilter.AccessControlsFilter.doFilter(AccessControlsFilter.java:79) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:237) at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:209) at net.bull.javamelody.PluginMonitoringFilter.doFilter(PluginMonitoringFilter.java:88) at org.jvnet.hudson.plugins.monitoring.HudsonMonitoringFilter.doFilter(HudsonMonitoringFilter.java:113) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at hudson.plugins.scm_sync_configuration.extensions.ScmSyncConfigurationFilter$1.call(ScmSyncConfigurationFilter.java:49) at hudson.plugins.scm_sync_configuration.extensions.ScmSyncConfigurationFilter$1.call(ScmSyncConfigurationFilter.java:44) at hudson.plugins.scm_sync_configuration.ScmSyncConfigurationDataProvider.provideRequestDuring(ScmSyncConfigurationDataProvider.java:106) at hudson.plugins.scm_sync_configuration.extensions.ScmSyncConfigurationFilter.doFilter(ScmSyncConfigurationFilter.java:44) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:59) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:138) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:49) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84) at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90) at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1637) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:190) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:564) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:317) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:110) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124) at org.eclipse.jetty.util.thread.Invocable.invokePreferred(Invocable.java:128) at org.eclipse.jetty.util.thread.Invocable$InvocableExecutor.invoke(Invocable.java:222) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:294) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:199) at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)