type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1858) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:446) at javax.servlet.http.HttpServlet.service(HttpServlet.java:696) at javax.servlet.http.HttpServlet.service(HttpServlet.java:809) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:198) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:138) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2459) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:132) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:118) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:593) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:116) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:126) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:152) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684) at java.lang.Thread.run(Thread.java:662)
root cause
java.lang.NullPointerException at ch.alpecole.lesson.LessonPageAction.execute(LessonPageAction.java:76) at org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:53) at org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:64) at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:48) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190) at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304) at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190) at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:280) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1858) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:446) at javax.servlet.http.HttpServlet.service(HttpServlet.java:696) at javax.servlet.http.HttpServlet.service(HttpServlet.java:809) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:198) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:209) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:138) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2459) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:132) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:118) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:593) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:116) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:126) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:595) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:432) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:954) at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:152) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684) at java.lang.Thread.run(Thread.java:662)