Again you have posted the exception without much detail for e.g. line no. Also since oyu haven't put in your entire code and since also your code is not indented properly it is difficult figuring out where the exception would be and hence why it would be occurring at all.
Still I present a hint here : Nullpointer exception occur at places where you use a null reference. This would be where you are using the dot operator (.) and the reference on the LHS of it is a null reference. IF you can figure out yourself where this would be happening in your program - great, but if not you can help us by posting the code part in question e.g. the main method and the entire stack trace with line numbers for the code part.