Hi can anyone solve view state error in my controller and VF page .

Controller: public with sharing class SVC_CR_CloneCRPackage_Ctl { private final static List<String> EXCLUDED_STATUSES = new List<String>{'Closed', 'Cancelled'}; public Boolean isCompleted {get; set;} public Boolean getRelatedAccountOnly {get; set;} public SelectableChangeRequest[] changeRequests {get; set;} private SVC_CP_QueryBuilder changeRequestsQB; private SVC_CR_Package__c crPackage; public SVC_CR_CloneCRPackage_Ctl() { getRelatedAccountOnly = true; isCompleted = false; crPackage = getCrPackage(); changeRequests = getChangeRequests(); } /** * Clones cr package to selected change requests */ public PageReference clonePackageToChangeRequests(){ Savepoint sp = Database.setSavepoint(); try { Set<ID> crIds = new Set<ID>(); for (SelectableChangeRequest record : changeRequests) { if (record.selected) { crIds.add(record.obj.Id); } } if (crIds.size() > 0) { return handleSuccess(SVC_CR_Package_Service.clonePackage(crIds, crPackage.Id)); } } catch (Exception e) { Database.rollback(sp); ApexPages.addMessage(SVC_ErrorHandler.logAndConvertToApexMessage(e)); } return null; } /** * Redirects to new package if there is one, * Displays list of new packages if there are many */ private PageReference handleSuccess(SVC_CR_Package__c[] newPackages) { if (newPackages.size() == 1) { return redirect(newPackages[0].Id); } showSuccess(newPackages); return null; } /** * Displays success message with list of new packages */ private void showSuccess(SVC_CR_Package__c[] newPackages) { for (SVC_CR_Package__c record : newPackages) { String message = Label.SVC_CR_ClonedPackages.replace('{0}', '/' + record.Id) .replace('{1}', record.Name); ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.INFO, message)); } ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.CONFIRM, Label.SVC_CR_ClonedPackageSuccess)); isCompleted = true; } /** * Redirects back to Opportunity record */ public PageReference cancel() { return redirect(crPackage.Id); } /** * Displays only change requests that has Account related to Opportunity */ public void withRelatedAccount() { getRelatedAccountOnly = true; changeRequests = getChangeRequests(); } /** * Displays all change requests */ public void withAllAccounts() { getRelatedAccountOnly = false; changeRequests = getChangeRequests(); } /** * Redirects to cr package page */ private PageReference redirect(ID recordId) { PageReference retURL = new PageReference('/' + recordId); retURL.setRedirect(true); return retURL; } /** * Queries cr package record */ private SVC_CR_Package__c getCrPackage() { return (SVC_CR_Package__c) SVC_CP_QueryBuilder.getInstance(SVC_CR_Package__c.SObjectType) .withAllFields() .withField('Change_Request__r.Opportunity__c') .withField('Change_Request__r.Account__r.Name') .withField('Change_Request__r.Account__r.Systems_Parent__c') .andWhereEq(SVC_CR_Package__c.Id, ApexPages.currentPage().getParameters().get('packageId')) .queryOne(); } /** * Queries change requests */ private SelectableChangeRequest[] getChangeRequests() { SVC_CP_QueryBuilder changeRequestsQB = SVC_CP_QueryBuilder.getInstance(SVC_Change_Request__c.SObjectType) .withAllFields() .withFields(new String[]{ 'Account__c', 'Account__r.Name', 'Account__r.Systems_Parent__c', 'Opportunity__c', 'Opportunity__r.Name', 'Change_Owner__c', 'Change_Owner__r.Name' }) .andWhereEq(SVC_Change_Request__c.RecordTypeId, SVC_CR_ChangeRequestService.getInstance().getProjectRecordTypeId()) // .andWhereNotIn( // SVC_Change_Request__c.Id, // SVC_CP_QueryBuilder.getInstance(SVC_CR_Package__c.SObjectType) // .withField(SVC_CR_Package__c.Change_Request__c) // .andWhereNotIn('Change_Request__r.Status__c', EXCLUDED_STATUSES) // ) .andWhereNotIn(SVC_Change_Request__c.Status__c, EXCLUDED_STATUSES); if (getRelatedAccountOnly) { Set<ID> relatedAccountIds = new Set<ID>{crPackage.Change_Request__r.Account__c}; if (crPackage.Change_Request__r.Account__r.Systems_Parent__c != null) { relatedAccountIds.add(crPackage.Change_Request__r.Account__r.Systems_Parent__c); } changeRequestsQB.andWhereIn('Account__r.Systems_Parent__c', relatedAccountIds); } SVC_Change_Request__c[] changeRequests = (SVC_Change_Request__c[]) changeRequestsQB.queryList(); SelectableChangeRequest[] crs = new SelectableChangeRequest[]{}; for (SVC_Change_Request__c cr : changeRequests) { crs.add(new SelectableChangeRequest(cr)); } return crs; } public class SelectableChangeRequest { public Boolean selected {get; set;} public SVC_Change_Request__c obj {get; set;} public SelectableChangeRequest(SVC_Change_Request__c obj) { this.obj = obj; this.selected = false; } } } Visual force page <apex:page controller="SVC_CR_CloneCRPackage_Ctl"> <apex:stylesheet value="{!URLFOR($Resource.BugPagination, 'DataTable/CSS/jquery.dataTables.min.css')}"/> <apex:stylesheet value="{!URLFOR($Resource.BugPagination, 'DataTable/ExternalCSS/ExternalCSS.css')}"/> <style> .message .messageText a { margin: 0; font-size: 100%; } </style> <script type="text/javascript" language="javascript" src="{!URLFOR($Resource.BugPagination, 'DataTable/JS/jquery-1.10.2.min.js')}"></script> <script type="text/javascript" language="javascript" src="{!URLFOR($Resource.BugPagination, 'DataTable/JS/jquery.dataTables.min.js')}"></script> <script type="text/javascript" language="javascript"> var j$ = jQuery.noConflict(); j$(document).ready(function() { initTable(); }); var initTable = function() { j$('table.dataTable').dataTable({ "bPaginate" : false, "bLengthChange" : false, "bFilter" : true, "bSort" : true, "bInfo" : true, "bAutoWidth" : false, "scrollY": "500px", "columnDefs": [ { "orderable": false, "targets": 0 }, ] }); }; </script> <apex:form > <apex:pageblock id="pbId"> <apex:pageMessages escape="false" id="messages"/> <apex:pageBlockButtons id="PgButtons"> <apex:commandButton value="Back" action="{!cancel}" immediate="true"/> <apex:commandButton value="Clone Package To Selected CRs" action="{!clonePackageToChangeRequests}" reRender="pbId" status="fetchStatus" rendered="{!NOT(isCompleted)}"/> </apex:pageBlockButtons> <apex:outputPanel > <apex:actionStatus id="fetchStatus"> <apex:facet name="start"> <img src="/img/loading.gif"/> </apex:facet> </apex:actionStatus> </apex:outputPanel> <apex:pageBlockSection id="pageSection" columns="1" rendered="{!NOT(isCompleted)}"> <apex:outputPanel id="accountFilters"> <apex:commandLink action="{!withRelatedAccount}" value="Show related Account" id="relatedAccountLink" rendered="{!!getRelatedAccountOnly}" reRender="pageSection" status="fetchStatus" onComplete="initTable();"/> <apex:commandLink action="{!withAllAccounts}" value="Show all Accounts" id="allAccountsLink" rendered="{!getRelatedAccountOnly}" reRender="pageSection" status="fetchStatus" onComplete="initTable();"/> </apex:outputPanel> <apex:pageBlockTable id="crTable" value="{!changeRequests}" var="item" styleClass="dataTable"> <apex:column id="row"> <apex:inputCheckbox id="selectBox" value="{!item.selected}"/> </apex:column> <apex:column > <apex:facet name="header">Change Request</apex:facet> <apex:outputLink value="/{!item.obj.Id}">{!item.obj.Name}</apex:outputLink> </apex:column> <apex:repeat value="{!$ObjectType.SVC_Change_Request__c.FieldSets.PackageCloneListView}" var="f"> <apex:column value="{!item.obj[f]}"/> </apex:repeat> </apex:pageBlockTable> </apex:pageBlockSection> </apex:pageblock> </apex:form> </apex:page>