Thread: Null Pointer Exception error

Sorry if this looks bad not too concerned with efficiency right now, getting null pointer
exception after while loop in constructor. Reading in from a file and setting values that are checked in the constructor. Commented problem area in caps.Also its not actually
finished i'm just testiing as I go. Now it is part of a project but I don't expect any more than simply pointing me in the right direction to fix this problem.
Updated exception occurs at bolded area no matter what the input. Compiler error java.lang.NullPointerException:null.

import java .util.Scanner ;
import java .io.*;
import java .util.ArrayList;
public class Room
{
    Scanner s = new Scanner(System.in);
    Scanner file = new Scanner("rooms.txt");
    private String hotelType;
    private String roomType;
    private String input;
    private int numOfRooms= 0;
    private int occNoMin = 0;
    private int occNoMax= 0 ;
    private int[] rates = new int[] {50,65,70,75,80,85,90,100};
    //ArrayList<String> roomFile = new ArrayList<String>();
    private  boolean cont = false;
 
    public Room()
    {
        System.out.println("Select hotel type -> eg.3-star - 5-star");
        input = s.next();
 
        while(cont != true)
        {
           // input = s.next();
            if(input.compareToIgnoreCase("3-star") == 0)
            {
                setHotelType();
                cont = true;
            }
            if(input.compareToIgnoreCase("4-star") == 0)
            {
                setHotelType();
                cont = true;
            }
            if(input.compareToIgnoreCase("5-star") == 0)
            {
                setHotelType();
                cont = true;
            }
            else
            {
                System.out.println("Not a known hotel star level");
                cont = true;
            }
        }
        [B]if(hotelType.compareToIgnoreCase("3-star") == 0)[/B] // NULL POINTER EXCEPTIONS OCCUR HERE DEPENDING ON INPUT
        {
            System.out.println("Select room type -> Classic  Double/Single/Twin/Family");//Deluxe/Executive
        }  
        else if(hotelType.compareToIgnoreCase("4-star") == 0)
        {
            System.out.println("Select room type -> Deluxe  Double/Single/Twin/Family");
        }
        else if(hotelType.compareToIgnoreCase("5-star") == 0)
        {
            System.out.println("Select room type -> Executive  Double/Single/Twin/Family");
        }
 
        input = s.next();
        setRoomType();
 
    }
 
    public void setHotelType()
    {
        String hotelCheck;
        ArrayList<String> arr = new ArrayList<String>();
        while(file.hasNext())
        {
            file.useDelimiter(",");
            hotelCheck = file.next() ;
            //hotelCheck = hotelCheck.substring(0,hotelCheck.length()-1);
            if(hotelCheck.compareToIgnoreCase("3-star")==0)
            {
                hotelType = hotelCheck;
            }
            else  if(hotelCheck.compareToIgnoreCase("4-star")==0)
            {
                hotelType = hotelCheck;
            }
            else  if(hotelCheck.compareToIgnoreCase("5-star")==0)
            {
                hotelType = hotelCheck;
            }
 
            //hotelCheck.split(",");
            //arr = hotelCheck;
            //for(int i= 0; i<hotelCheck.length();i ++)
            //{
            //  if(hotelCheck[i].compareToIgnoreCase(input) ==0)
            //{
            // hotelCheck[i] = hotelType;
            //}
            //}
        }
 
    }
 
    public void setRoomType()
    {
        String roomCheck;
        while(file.hasNext())
        {
            file.useDelimiter(",");
            roomCheck = file.next() ;
 
            if(roomCheck.compareToIgnoreCase("Single")==0)
            {
                roomType = roomCheck;
            }
            if(roomCheck.compareToIgnoreCase("Twin")==0)
            {
                roomType = roomCheck;
            }
            if(roomCheck.compareToIgnoreCase("Double")==0)
            {
                roomType = roomCheck;
            }
            if(roomCheck.compareToIgnoreCase("Family")==0)
            {
                roomType = roomCheck;
            }
 
        }
    }
 
    public String getHotel()
    {
        return hotelType;
    }
 
    public String getRoom()
    {
        return roomType;
    }
 
    public int getNumRooms()
    {
        return numOfRooms;
    }
 
    public int getMinOcc()
    {
        return occNoMin;
    }
 
    public int getMaxOcc()
    {
        return occNoMax;
    }
 
 
}