Android how to store all ArrayList<ArrayList<String>> values into ArrayList<String> :       stylistIDArray=differentGenderServicesAdapter.getSelectedStylistIdArray();
                            durationArray=differentGenderServicesAdapter.getSelectedDurArray();
    
                            ArrayList<String>stylistId=new ArrayList<>();
                            ArrayList<String>duration=new ArrayList<>();
    
                           for(int i=0; i<stylistIDArray.size(); i++) {
                               stylistId=stylistIDArray.get(i);
                               duration=durationArray.get(i);
                           }

I am having issue to store all values of ArrayList<ArrayList<String>> into ArrayList<String> here stylistIDArray and durationArray is arrayofarray i want to store all values in stylistId and duration.The stylistid and duration are array of string.when i am trying to add its storing only the last position of arrayofarrayList.