java.lang.NullPointerException

java.lang.NullPointerException
at jp.co.iret.accordia.turbine.screens.user.practice.DirectlyPracticeCourse.handlePerform(DirectlyPracticeCourse.java:53)
at jp.co.iret.accordia.turbine.screens.user.UserCommon.mainPerform(UserCommon.java:42)
at jp.co.iret.accordia.turbine.screens.common.AccordiaCommon.doBuildTemplate(AccordiaCommon.java:95)
at org.apache.turbine.modules.screens.VelocitySecureScreen.doBuildTemplate(VelocitySecureScreen.java:64)
at jp.co.iret.accordia.turbine.screens.common.AccordiaCommon.doBuildTemplate(AccordiaCommon.java:60)
at org.apache.turbine.modules.screens.TemplateScreen.doBuild(TemplateScreen.java:100)
at org.apache.turbine.modules.Screen.build(Screen.java:57)
at org.apache.turbine.modules.ScreenLoader.eval(ScreenLoader.java:107)
at org.apache.turbine.modules.layouts.VelocityOnlyLayout.doBuild(VelocityOnlyLayout.java:92)
at org.apache.turbine.modules.Layout.build(Layout.java:53)
at org.apache.turbine.modules.LayoutLoader.exec(LayoutLoader.java:101)
at org.apache.turbine.modules.pages.DefaultPage.doBuild(DefaultPage.java:168)
at org.apache.turbine.modules.Page.build(Page.java:53)
at org.apache.turbine.modules.PageLoader.exec(PageLoader.java:101)
at org.apache.turbine.Turbine.doGet(Turbine.java:789)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:704)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:474)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:409)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)
at jp.co.iret.accordia.utils.PracticeDispatherServlet.doPerform(PracticeDispatherServlet.java:105)
at jp.co.iret.accordia.utils.PracticeDispatherServlet.doGet(PracticeDispatherServlet.java:46)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at jp.co.iret.common.servlet.filters.ConvertInputHtmltagFilter.doFilter(ConvertInputHtmltagFilter.java:151)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at jp.co.iret.common.servlet.filters.RemoveTabCharFilter.doFilter(RemoveTabCharFilter.java:99)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at jp.co.iret.common.servlet.filters.MultipartFilter.doFilter(MultipartFilter.java:98)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.cluster.tcp.ReplicationValve.invoke(ReplicationValve.java:141)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:300)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:374)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:743)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:675)
at org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:866)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:595)