An unexpected error occured

Method onFormSubmitted of interface org.apache.wicket.markup.html.form.IFormSubmitListener targeted at [SignInForm [Component id = signInForm]] on component [SignInForm [Component id = signInForm]] threw an exception
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org.apache.wicket.WicketRuntimeException: Method onFormSubmitted of interface org.apache.wicket.markup.html.form.IFormSubmitListener targeted at [SignInForm [Component id = signInForm]] on component [SignInForm [Component id = signInForm]] threw an exception
at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268)
at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:216)
at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:240)
at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:226)
at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:840)
at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64)
at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:254)
at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:211)
at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:282)
at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:244)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:188)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:267)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.tomee.catalina.OpenEJBValve.invoke(OpenEJBValve.java:45)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor311.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258)
... 28 more
Caused by: javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is:
javax.ejb.EJBTransactionRolledbackException: The transaction has been marked rollback only because the bean encountered a non-application exception :java.lang.NullPointerException : null
at org.apache.openejb.core.ivm.BaseEjbProxyHandler.convertException(BaseEjbProxyHandler.java:363)
at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:283)
at com.commafeed.backend.services.UserService$LocalBeanProxy.login(com/commafeed/backend/services/UserService.java)
at com.commafeed.frontend.CommaFeedSession.authenticate(CommaFeedSession.java:54)
at org.apache.wicket.authroles.authentication.AuthenticatedWebSession.signIn(AuthenticatedWebSession.java:65)
at org.apache.wicket.authroles.authentication.panel.SignInPanel.signIn(SignInPanel.java:221)
at org.apache.wicket.authroles.authentication.panel.SignInPanel.access$100(SignInPanel.java:51)
at org.apache.wicket.authroles.authentication.panel.SignInPanel$SignInForm.onSubmit(SignInPanel.java:296)
at org.apache.wicket.markup.html.form.Form$9.component(Form.java:1246)
at org.apache.wicket.markup.html.form.Form$9.component(Form.java:1240)
at org.apache.wicket.util.visit.Visits.visitPostOrderHelper(Visits.java:274)
at org.apache.wicket.util.visit.Visits.visitPostOrder(Visits.java:245)
at org.apache.wicket.markup.html.form.Form.delegateSubmit(Form.java:1239)
at org.apache.wicket.markup.html.form.Form.process(Form.java:921)
at org.apache.wicket.markup.html.form.StatelessForm.process(StatelessForm.java:87)
at org.apache.wicket.markup.html.form.Form.onFormSubmitted(Form.java:767)
at org.apache.wicket.markup.html.form.Form.onFormSubmitted(Form.java:700)
... 32 more
Caused by: javax.ejb.EJBTransactionRolledbackException: The transaction has been marked rollback only because the bean encountered a non-application exception :java.lang.NullPointerException : null
at org.apache.openejb.core.ivm.BaseEjbProxyHandler.convertException(BaseEjbProxyHandler.java:345)
at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:283)
at com.commafeed.backend.dao.UserDAO$LocalBeanProxy.findByName(com/commafeed/backend/dao/UserDAO.java)
at com.commafeed.backend.services.UserService.login(UserService.java:24)
at sun.reflect.GeneratedMethodAccessor309.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:181)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:163)
at org.apache.openejb.cdi.CdiInterceptor.invoke(CdiInterceptor.java:130)
at org.apache.openejb.cdi.CdiInterceptor.access$000(CdiInterceptor.java:43)
at org.apache.openejb.cdi.CdiInterceptor$1.call(CdiInterceptor.java:67)
at org.apache.openejb.cdi.CdiInterceptor.aroundInvoke(CdiInterceptor.java:73)
at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:181)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:163)
at org.apache.openejb.monitoring.StatsInterceptor.record(StatsInterceptor.java:180)
at org.apache.openejb.monitoring.StatsInterceptor.invoke(StatsInterceptor.java:99)
at sun.reflect.GeneratedMethodAccessor31.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:181)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:163)
at org.apache.openejb.core.interceptor.InterceptorStack.invoke(InterceptorStack.java:138)
at org.apache.openejb.core.stateless.StatelessContainer._invoke(StatelessContainer.java:239)
at org.apache.openejb.core.stateless.StatelessContainer.invoke(StatelessContainer.java:191)
at org.apache.openejb.core.ivm.EjbObjectProxyHandler.synchronizedBusinessMethod(EjbObjectProxyHandler.java:256)
at org.apache.openejb.core.ivm.EjbObjectProxyHandler.businessMethod(EjbObjectProxyHandler.java:251)
at org.apache.openejb.core.ivm.EjbObjectProxyHandler._invoke(EjbObjectProxyHandler.java:85)
at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:279)
... 47 more
Caused by: java.lang.NullPointerException
at com.commafeed.backend.dao.UserDAO.findByName(UserDAO.java:19)
at sun.reflect.GeneratedMethodAccessor283.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:181)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:163)
at org.apache.openejb.cdi.CdiInterceptor.invoke(CdiInterceptor.java:130)
at org.apache.openejb.cdi.CdiInterceptor.access$000(CdiInterceptor.java:43)
at org.apache.openejb.cdi.CdiInterceptor$1.call(CdiInterceptor.java:67)
at org.apache.openejb.cdi.CdiInterceptor.aroundInvoke(CdiInterceptor.java:73)
at sun.reflect.GeneratedMethodAccessor32.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:181)
at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(R