Below is the method which is throwing "Attempt to de-reference a null object, 3332".Can somebody help?
it is called under Before insert and  Update
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if(Trigger.isBefore){
        if(Trigger.isInsert)
            R2_CLS_CaseTriggerMethods.checkStatusCountAndDate(news, null);
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if(Trigger.isUpdate)
            R2_CLS_CaseTriggerMethods.checkStatusCountAndDate(news, olds);
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public static void checkStatusCountAndDate(List<Case> news, List<Case> olds){
        try{
            if(R1_CLS_LogHelper.isRunningTest()){throw new R1_CLS_LogHelper.R1_Exception('test');} 

            Id rtIdExp = Schema.SObjectType.Case.getRecordTypeInfosByName().get('Expediente').getRecordTypeId();
            Id rtIdCons = Schema.SObjectType.Case.getRecordTypeInfosByName().get('Consulta').getRecordTypeId();
            Id rtIdGDPR = Schema.SObjectType.Case.getRecordTypeInfosByName().get('GDPR').getRecordTypeId();

            //fill the set with the possible status to close a transction
            Set<String> statusEndTransactionSet = new Set<String>();
            statusEndTransactionSet.add('Closed');
            statusEndTransactionSet.add('Cancelled');
            statusEndTransactionSet.add('Waiting on Iberia');
            statusEndTransactionSet.add('Waiting on Cliente');

            for (Integer i = 0; i < news.size(); i++) {
                if (news[i].RecordTypeId == rtIdExp || news[i].RecordTypeId == rtIdCons || news[i].RecordTypeId == rtIdGDPR) {
                    //is insert
                    if (olds == null) {
                        //check if the status corresponding to a close transaction
                        if (statusEndTransactionSet.contains(news[i].Status)) {
                            news[i].R2_CAS_DAT_First_Transaction_date__c = System.Today();
                            news[i].R2_CAS_NUM_Count_Number_Transaction__c = 1;
                        }
                        else if (news[i].Status == 'Reabierto') {
                            news[i].R2_CAS_NUM_Count_Number_Reopen__c = 1;
                            news[i].R2_CAS_DAT_First_Reopen_Date__c = System.Today();
                            news[i].R2_CAS_DAT_Last_Reopen_Date__c = System.Today();
                        }
                    }
                    // is update
                    else {
                        if (!statusEndTransactionSet.contains(olds[i].Status) && statusEndTransactionSet.contains(news[i].Status)) {
                            news[i].R2_CAS_NUM_Count_Number_Transaction__c = olds[i].R2_CAS_NUM_Count_Number_Transaction__c + 1;
                            if (olds[i].R2_CAS_DAT_First_Transaction_date__c == null) {
                                news[i].R2_CAS_DAT_First_Transaction_date__c = System.Today();
                            }
                        }
                        else if (olds[i].Status != news[i].Status && statusEndTransactionSet.contains(olds[i].Status) && news[i].Status == 'Reabierto') {
                            news[i].R2_CAS_NUM_Count_Number_Reopen__c = olds[i].R2_CAS_NUM_Count_Number_Reopen__c + 1;
                            news[i].R2_CAS_DAT_Last_Reopen_Date__c = System.Today();
                            if (olds[i].R2_CAS_DAT_First_Reopen_Date__c == null) {
                                news[i].R2_CAS_DAT_First_Reopen_Date__c = System.Today();
                            }
                            if (olds[i].R2_CAS_DAT_Last_Reopen_Date__c != null) {
                                news[i].R2_CAS_DAT_Penultimate_Reopen_Date__c = olds[i].R2_CAS_DAT_Last_Reopen_Date__c;
                            }
                        }
                    }
                }
            }
        }catch(Exception exc){
            R1_CLS_LogHelper.generateErrorLog('R2_CLS_CaseTriggerMethods.checkStatusCountAndDate()', '', exc.getmessage()+', '+exc.getLineNumber(), 'Case');
        }
    }