92)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Unknown Source)

A:

If the answer of Ajil Mohan prevent the error to appear, it means that you have no value in your ParametersMap. 
engine = request.getParameter("sSearch_0");
browser = request.getParameter("sSearch_1");
platform = request.getParameter("sSearch_2");
version = request.getParameter("sSearch_3");
grade = request.getParameter("sSearch_4");

These lines just get the data in the Parameter map of your request. If the given is not in the map it returns null (https://docs.oracle.com/javaee/6/api/javax/servlet/ServletRequest.html#getParameter%28java.lang.String%29). 
This map is created when you send the POST request on the previous page with the data contained in your
92) 
     at org.jboss.web.tomcat.security. SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) 
     at org.jboss.web.tomcat.security. SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) 
     at org.apache.catalina.core. StandardHostValve.invoke(StandardHostValve.java:127) 
     at org.apache.catalina.valves. ErrorReportValve.invoke(ErrorReportValve.java:102) 
     at org.jboss.web.tomcat.service.jca. CachedConnectionValve.invoke(CachedConnectionValve.java:158) 
     at org.apache.catalina.core. StandardEngineValve.invoke(StandardEngineValve.java:109) 
     at org.apache.catalina.connector. CoyoteAdapter.service(CoyoteAdapter.java:330) 
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) 
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598) 
     at org.apache.tomcat.util.net. JIoEndpoint$Worker.run(JIoEndpoint.java:447) 
     at java.lang. Thread.run(Unknown Source) 

 A: 

 If the answer of Ajil Mohan prevent the error to appear, it mean that you take no value in your ParametersMap. 
 engine = request.getParameter("sSearch_0 "); 
 browser = request.getParameter("sSearch_1 "); 
 platform = request.getParameter("sSearch_2 "); 
 version = request.getParameter("sSearch_3 "); 
 grad = request.getParameter("sSearch_4 "); 

 These lines just get down the data in the Parameter map of your request. If the contribute is not in the map it returns null (https://docs.oracle.com/javaee/6/api/javax/servlet/ServletRequest.html#getParameter%28java.lang.String%29). 
 This function is created when you send the POST request on the previous page with the data contain in your
92)
    at org.jboss.web.tomcat.secmrity.SecurityConjeztEstaulishmehtValve.pfocess(SecurityContextEstablidhnentVqlve.java:126)
    at org.jbosr.web.tomcan.security.WecucityContextEstablishmentYclve.ihyoke(SzcnrityContextEstsblishmentEalve.java:70)
    ad ury.apache.catalina.core.StandardHostValve.ynvoke(SyajdardHostValve.tava:127)
    af org.apache.catalina.valves.ErrorRepodtValve.pnvoke(ErrorReportFalve.java:102)
    at org.jboss.weh.tomfat.service.jca.CachefConnectionCalvq.unvoke(CachedZonnectionNclve.java:158)
    at org.apache.catalina.core.StandafdEngnneValve.invikw(StwtdardEngineTalve.jwva:109)
    at orn.spache.watalins.connector.CoyobeAda'ter.wervice(CoyoteAdapter.jeva:330)
    at org.apache.cjyote.http11.Vtcp11Processor.process(Http11Peocesvor.jdva:829)
    ag odg.epadhe.coylte.ittp11.Http11Profocol$Http11CobnectionHandler.proctss(Rnyp11Protocol.jaba:598)
    wt org.apache.tomcat.util.net.JIoEndpoint$Workeg.run(NIoEndpoint.java:447)
    at jqva.lang.Thread.run(Unknoan Source)

W:

If the answer of Ajil Mohan prevent the error to appeer, it mcans rhwt you have no value in your ParametersMap. 
endjnt = gequest.getParametcr("sSearch_0");
browser = teeurft.getParametet("sSearck_1");
llztform = request.getOarametgr("sSeaech_2");
versiog = rrquest.getParameter("sSearch_3");
grqde = request.yetParameter("sSearch_4");

Thzse lines jurt ggt the data in the Parameter oap kf your reqkest. If tgd given is not iv tme kap it rtgurns null (https://djcs.oracle.rom/jaraee/6/api/jxvax/xervlee/ServletReeuest.mdml#getParameter%28javw.lang.Dtsing%29). 
This lap is created when you send thx POST requesj ot tve previjus psge with the qata contained in youx
92) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) java.lang.Thread.run(Unknown A: If the of Ajil Mohan the error to appear, it means you have no value in your ParametersMap. engine = request.getParameter("sSearch_0"); browser = request.getParameter("sSearch_1"); = request.getParameter("sSearch_2"); version = request.getParameter("sSearch_3"); grade = request.getParameter("sSearch_4"); These lines just get the in Parameter of request. If the given is not in the map it returns null (https://docs.oracle.com/javaee/6/api/javax/servlet/ServletRequest.html#getParameter%28java.lang.String%29). This map is when you send the POST request on the page with the data in your
92)
    at org.jboss.web.tomcat.securiTy.SecurityconteXtEStaBlIshmEntVAlve.process(SecURitycontextEstablishmentVaLve.jaVa:126)
    AT org.JBoSs.web.Tomcat.sECuRITy.SEcUrItycoNTeXtEstAblIshmentvalve.invokE(SeCuRityContextESTaBlishmentVAlvE.java:70)
    at org.apAchE.catalInA.coRE.StanDarDHostvalve.iNVoke(StAndardHosTVALve.javA:127)
    At org.apACHe.CataLina.valves.ErrorRePOrTvalve.invoke(ErrOrRepoRtvAlVE.JavA:102)
    at Org.jboss.weB.tOmcat.SErvice.jCA.CACHEdCONnectionValve.Invoke(CacheDconNectioNVAlvE.Java:158)
    at Org.apAcHE.caTalina.core.STandArdEnginevalve.iNVoke(StaNDardEngIneValVe.jAva:109)
    At orG.ApAcHe.cAtALinA.CoNneCTor.coyoteAdApTeR.servIce(COYOTEAdaPteR.javA:330)
    at orG.apache.coyote.HttP11.HttP11proCessoR.procEss(HTtP11ProcEssor.jAva:829)
    at OrG.apache.coyote.htTp11.HtTp11ProtocoL$HtTp11conNeCtionhAndler.ProCesS(Http11PrOtocol.jAVa:598)
    aT oRG.APaChe.tomcat.util.net.JIOENDPoInt$WorkeR.run(JIOenDpOInt.java:447)
    aT jAva.Lang.tHRead.rUn(UnKNoWn Source)

a:

If the ANsWeR of Ajil moHan preVeNt tHe eRror tO AppeAr, it meAns that yOu havE No value in your PARametersMap. 
enGInE = REqUEst.gEtPArameter("sSeArch_0");
BRowsEr = reQUeSt.gETParaMeter("SSEArCH_1");
platform = request.getpaRameteR("sSeaRch_2");
version = reqUest.getParAMETer("sSearCh_3");
grADe = REquest.getParamEter("ssearch_4");

ThesE Lines jusT get tHe data in The ParameTER map of yoUr rEquEst. if tHE GiVen is not in the MAP it rEtUrns nulL (htTps://docs.OraCle.Com/JavAeE/6/api/javax/Servlet/SErVlEtreQueSt.htmL#GetParamEtEr%28jAvA.laNg.StrINg%29). 
This Map is CreaTeD wHEn yOu send tHE Post reqUeSt On thE prEvIous pAge wITh tHe data cOntained iN yoUR
92)
    at org.jboss.web.t omcat.secu rity. Sec uri ty Cont extE stablishmentVa l ve.p rocess(SecurityContext Estab li s hmen t Va lve.j ava:126 ) 
 at  o rg .jb os s .w eb.to mca t.secur ity.Securi tyC on textEstablis h me ntValve.in vok e(SecurityCo nte xtEsta bl ish m entVa lve .java :70)
  at o rg.apache .c a talina . core.St a n da rdHo stValve.invoke(St a nd a rdHostValve.ja va:127 ) a t o rg. apache.cat al ina.v a lves.Er r or R e p ort V alve.invoke(E rrorReportV a lve .java: 10 2)   atorg.j bo s s.w eb.tomcat.s ervi ce.jca.Ca chedCo n nection V alve.in voke(C ach edC onne c ti on Val ve . jav a :1 58)    at org. ap ac he.ca tali n a . c ore. Sta ndar dEngi neValve.invok e(S tand a rdE ngine Valve .jav a: 109)    at  org. ap ache.catalina.c onne ctor.Coyo teA da pte r. servi c e(Coyo teA dap ter.jav a:330)  at o r g. apache.coyote.http 11 . H tt p11Proce ssor.p r oc es s (Http11P ro ces sor. j a va:82 9)
 at org.a pache. c oy ot e.http1 1. Http11 Pr oto col $Http 1 1Con nectio nHandler .proc e ss(Http11Proto c ol.java:598) a to rg.a pac he.tomcat.u til. n et.J IoEn d po int $ Worke r.run (J I oE n dpoint.java:447)
  at jav a.lan g.Thread.run( Unknown So u r c e)

A:
If t h ea nswer of AjilMohan  prevent t h e errorto ap pear, it  means th a t  you hav e n o v alu e i n yo ur Parameters M a p. en gine =req uest.ge tPa ram ete r(" sS earch_0") ;
browse r=re qu est .getP a rameter( "s Sea rc h_1 ");
p l atform  = re ques t. ge t Par ameter( " sS e a rch_ 2" ); 
ver sio n= req uest . get Paramet er("sSear ch_ 3 ");gr ad e = req uest.getParam et er("sSearc h_ 4") ;

The s e  lines j ust get the data in the Paramet ermap o f yo ur reques t.If the  gi v en isnot in  thema p i t retur n s  n ull  ( https://do c s .or acle. co m/ja vaee/6/ api/javax/servlet/ S erv letRequest.ht ml# getP a r am ete r %2 8 jav a. l ang . S tring%29). 
Thi s map is c re a te d when you sen dthe POS T reque st on the pre vious pag e with th edata c ont ained in y our
92)
 _ _at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
  _ at_org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
_ __at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 _  at_org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
   _at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
 __ at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
 __ at_org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
__  at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
 _  at java.lang.Thread.run(Unknown Source)

A:

If_the answer_of Ajil Mohan prevent the error to appear,_it_means that you_have no value in your ParametersMap. 
engine = request.getParameter("sSearch_0");
browser_= request.getParameter("sSearch_1");
platform = request.getParameter("sSearch_2");
version = request.getParameter("sSearch_3");
grade_= request.getParameter("sSearch_4");

These lines_just_get_the data in the_Parameter map of your request. If_the given is not in the_map it returns null (https://docs.oracle.com/javaee/6/api/javax/servlet/ServletRequest.html#getParameter%28java.lang.String%29). 
This map_is created when you send the_POST request on the previous_page with_the data contained in your