After upgrading the Description Setter plugin from 1.4 to 1.5, the following 500 error is thrown when attempting to save a job that has the description setter plugin enabled (verified behavior in freestyle and maven jobs). I was able to get unblocked by rolling back to version 1.4 of the plugin.

Exception:
Stacktrace:

java.lang.IllegalArgumentException
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:532)
at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:391)
at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:344)
at hudson.plugins.descriptionsetter.DescriptionSetterPublisher$DescriptorImpl.newInstance(DescriptionSetterPublisher.java:192)
at hudson.plugins.descriptionsetter.DescriptionSetterPublisher$DescriptorImpl.newInstance(DescriptionSetterPublisher.java:171)
at hudson.util.DescribableList.rebuild(DescribableList.java:139)
at hudson.maven.MavenModuleSet.submit(MavenModuleSet.java:697)
at hudson.model.Job.doConfigSubmit(Job.java:968)
at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:519)
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:616)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:185)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:101)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:54)
at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:74)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:492)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:180)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:492)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:408)
at org.kohsuke.stapler.Stapler.service(Stapler.java:117)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
at winstone.ServletConfiguration.execute(ServletConfiguration.java:249)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:335)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:378)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:94)
at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:304)
at org.jvnet.hudson.plugins.monitoring.HudsonMonitoringFilter.doFilter(HudsonMonitoringFilter.java:31)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:97)
at hudson.plugins.audit_trail.AuditTrailFilter.doFilter(AuditTrailFilter.java:64)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:97)
at org.jvnet.hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:47)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:97)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:86)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:47)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:166)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:173)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:66)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)
at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:244)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)
at java.lang.Thread.run(Thread.java:636)