Help in null pointer exception

Question

I have a null pointer exception and i cant figure out which variable is null,
This is my servlet code.
ArrayList pmArray = pDAO.getPlacemarkByRegion(northEastLong, northEastLat, southWestLat, southWestLat);
            //loop through the placemark
            for ( int i=0; i< pmArray.size();i++) {
                Placemark pm = (Placemark)pmArray.get(i);
                // parse string
                String pmId = pm.getPlacemarkid()+"";
                String pmLat = pm.getLatitude()+"";
                String pmLong = pm.getLongtitude()+"";
                String s = "{\"markers\":[ " +
                        "{\"placemarkid\" : + pmId , \"latitude\" :  + pLat , \"longtitude\": + pmLong} + ]}";
                 System.out.println(s);This is my DAO class
public ArrayList getPlacemarkByRegion(double northEastLong, double northEastLat, double southWestLong, double southWestLat)When i get the placemark andNullPointerException appear. I think that my Arraylist is incorrect, I have also try-catch exception in the servlet but it still show me null pointer. Can anyone please kindly guide me?
Message was edited by:
peebu

Answer 1

hmm, i have solved my sql syntext already, but i still manage to get pmArray null.
I have check through my codes but pmArray is still null.
try{
        pDAO = new PlacemarkDAO();
        ArrayList pmArray = pDAO.getPlacemarkByRegion(northEastLong,northEastLat,southWestLong, southWestLat);
        if(pmArray!=null && pmArray.size()>0){ //Check if the method pDao.getPlacemarkByRegion return a null to pmArray
            for ( int i=0; i< pmArray.size();i++) {
                Placemark pm = (Placemark)pmArray.get(i);
                if(pm!=null){ //check if the instance pm is null
                    String pmId = pm.getPlacemarkid()+"";
                    String pmLat = pm.getLatitude()+"";
                    String pmLong = pm.getLongtitude()+"";
                   out.println("{\"markers\" : [ {\"placemarkid\":, \"latitude\" :, \"longtitude\" :}," +
                                    "{\"placemarkid\" :, \"latitude\":, \"longtitude\" :}," +
                                    "{\"placemarkid\" :, \"latitude\" :, \"longtitude\" :}" +
                }else{
                   System.out.println("Error in: "+i + " element"); //if pm instance is null then return the element position of the pmArray
        }else{
            System.out.println("pmArray is null");
       catch(Exception e)
           e.printStackTrace();
        out.close();
    }Hmm, anyone can tell me why is it still null ? is it still related to my DAO class? Or i have lacked out something?Can anyone please give me pointers and guide me along?