org.apache.jasper.JasperException: An exception occurred processing JSP page [/v4/common/Main.jsp] at line [41]

38:     Advert advert = screen.getAdvert();
39:     
40:     //Get list of current adverts
41:     AdvertList advertList = screen.getAdvertList();                 //Adverts for normal listing
42:     AdvertList promotedAdvertList = screen.getPromotedAdvertList(); //Adverts to display in side-panels
43:     AdvertList popularAdvertList = screen.getPopularAdvertList();   //Adverts to display as popular
44:     AdvertList kidsAdvertList = screen.getKidsAdvertList();         //Adverts to display as popular among kids


Stacktrace:
	at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:588)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:481)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:467)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:392)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:311)
	at com.extras.v4.shared.control.Controller.processRequest(Unknown Source)
	at com.extras.v4.shared.control.Controller.doGet(Unknown Source)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at load.ActionCounterFilter.doFilter(Unknown Source)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:486)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
	at com.extras.v4.util.MainCache.getAdvertListSorted(Unknown Source)
	at com.extras.v4.util.MainCache.getAdvertList(Unknown Source)
	at com.extras.v4.common.screens.MainScreen.getAdvertList(Unknown Source)
	at org.apache.jsp.v4.common.Main_jsp._jspService(Main_jsp.java:196)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443)
	... 40 more