SEVERE: Servlet.service() for servlet jsp threw exception

出現下面的錯誤，請檢查下jsp-api.jar和servlet-api.jar包是否出現沖突。

SEVERE: Servlet.service() for servlet jsp threw exception

java.lang.NullPointerException

    at org.apache.jsp.pages.login_jsp._jspService(login_jsp.java:90)

    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:386)

    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)

    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)

    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)

    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)

    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)

    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)

    at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1083)

    at org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:295)

    at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:396)

    at org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:347)

    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:232)

    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)

    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)

    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)

    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at com.b2r.i18n.filter.CharsetFilter.doFilter(CharsetFilter.java:24)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at com.b2r.monitor.filter.P3PResponseFilter.doFilter(P3PResponseFilter.java:35)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at com.b2r.rewards.security.filter.SecurityInterceptorFilter.doFilter(SecurityInterceptorFilter.java:61)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at com.b2r.rewards.security.filter.XSSContentFilter.doFilter(XSSContentFilter.java:62)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at com.b2r.rewards.security.filter.Log4JMDCFilter.doFilter(Log4JMDCFilter.java:38)

    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)

    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)

    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)

    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)

    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)

    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)

    at java.lang.Thread.run(Thread.java:662)