avax.servlet.ServletException: java.lang.RuntimeException: Failed to instantiate class hudson.triggers.SCMTrigger from {"scmpoll_spec":"0* * * *"}
	org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:616)
	org.kohsuke.stapler.Stapler.invoke(Stapler.java:659)
	org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:241)
	org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
	org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:574)
	org.kohsuke.stapler.Stapler.invoke(Stapler.java:659)
	org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:241)
	org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
	org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:574)
	org.kohsuke.stapler.Stapler.invoke(Stapler.java:659)
	org.kohsuke.stapler.Stapler.invoke(Stapler.java:488)
	org.kohsuke.stapler.Stapler.service(Stapler.java:162)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:95)
	hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:87)
	hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:47)
	hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
	hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
	hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
	hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)

root cause