Hi All,
I am trying to hide the custom button based on permission set.For that i already wrote a code but it is giving me an error.

 public void Custombutton()
         {
                for(PermissionSetAssignment permission : [SELECT Id, PermissionSet.Name FROM PermissionSetAssignment WHERE AssigneeId =:UserInfo.getUserId() ])
            {
                 permissionSetNameList.add(permission.PermissionSet.Name); 
                                          
            }          
            userPermissionList.addAll(permissionSetNameList);   
            
            for(User userIterator : [SELECT Id, Profile.Name FROM User WHERE Id =: UserInfo.getUserId()])
            {
                userProfileSet.add(userIterator.Profile.Name);
            }                 
            if( userPermissionList.contains('Test_Permission')== true)
            {
                relatedListFlag = true;       
            } 

I called the Custombutton() in controller .
Afte that i added the relatedListflag in rendered property of the button.

Vf Page Code
<apex:commandButton id="hideEditbtn1" Styleclass="btn btn-primary" action="{!makeFormEdit}" rendered="{!!isEditMode && relatedListFlag}" value="Edit" reRender="contentPanel,actProjHist,formId" oncomplete="loadToggle();hidePOC();showHeader();hideHelptext();"> </apex:commandButton> &nbsp;&nbsp;  

But when i tested the app with  Test_Permission . it is giving me an error
  System.NullPointerException: Attempt to de-reference a null object       

Please help me on this.

Thanks,
Anish