Hi suree

      this is my code.and my need is when ever we share something in chatter the user recieve the message their mobile.but this code is working and we share data in chatter it shows the exception

 System.Null Pointer Exception:Attemt to De-Reference a null object:trigger.testing Options

please suggest me 

trigger Testing on FeedItem (after insert)
{
List<smagicbasic__smsMagic__c> smsObjects = new List<smagicbasic__smsMagic__c>();
List<smagicbasic__smsMagic__c> smsObjects1 = new List<smagicbasic__smsMagic__c>();
String tplText = null;
String query = null;
List<sObject> sObjects = null;
Id FeedItemId = null;
 List<CollaborationGroup> esl;
 list<CollaborationGroupMember> cgm;
 list<user> uu;
 list<user> uu1;
 list<EntitySubscription> es2;
Id userId = UserInfo.getUserId();
Id orgId = UserInfo.getOrganizationId();
public list<Id> uid = new List<Id>();
public list<Id> uid1 = new List<Id>();
public Set<ID> es1Ids = new Set<ID>();
public Set<ID> es2Ids = new Set<ID>();
for (FeedItem f : Trigger.new)
  {
if(f.parentId !=null )
  {
esl = [SELECT id, name FROM CollaborationGroup WHERE id =: f.parentId];
        system.debug('********** parent id :'+ f.parentid);
         
es2= [SELECT id, parentid, subscriberid, parent.name FROM EntitySubscription
               WHERE parentid = : f.parentid];
for(CollaborationGroup es:esl)
  {
 cgm =  [select id,MemberId from CollaborationGroupMember where CollaborationGroupId = : es.id];
 }
}
if(cgm.size()>0)

   {
     for(CollaborationGroupMember cc : cgm)
     {
       es1Ids.add(cc.memberid);
       }
uu = [select id,MobilePhone,name from user where id IN: es1Ids];
  system.debug('**********uuuuuuuuu id :'+uu);   
}
System.debug('--- Followers list: ' + uu);
for(EntitySubscription e3:es2)
{
if(e3.subscriberid != null)
{
es2Ids.add(e3.subscriberid);
}
}
uu1 = [select id,MobilePhone,name from user where id IN: es2Ids];

for(user u1 :uu1)
       {
        if(u1.MobilePhone != null)
        {
        tplText = f.Body;
        smagicbasic__smsMagic__c smsObj = new smagicbasic__smsMagic__c();
        smsObj.smagicbasic__PhoneNumber__c = u1.MobilePhone;
        smsObj.smagicbasic__SMSText__c = tplText;
        smsObj.smagicbasic__senderId__c = 'smsMagic';
        smsObj.smagicbasic__Name__c = u1.Name;
        smsObjects1.add(smsObj);
       }
        }
   
insert smsObjects1;



for(user u :uu)
{
if(u.MobilePhone != null){
   system.debug('*********Mobile Phone :'+u.mobilephone);
tplText = f.Body;
smagicbasic__smsMagic__c smsObj = new smagicbasic__smsMagic__c();
smsObj.smagicbasic__PhoneNumber__c = u.MobilePhone;
smsObj.smagicbasic__SMSText__c = tplText;
smsObj.smagicbasic__senderId__c = 'smsMagic';
smsObj.smagicbasic__Name__c = u.Name;
smsObjects.add(smsObj);

}
}
insert smsObjects;
}
}

It looks like this error is comming from some other trigger trigger.testing Options  when you are running FeedItem trigger , testing option trigger is also firing (the reason may be both triggers are following same criteria) check with that.

If this answers your question mark it as solution, Its up to you.

no i have only one trigger.