Getter, Setter & NullPointerException

Question

Firstly, I am trying to assign the value for array I initialized locally. The class type of the array is stored inside another class and the variable is private so I am using getter and setter to set the value. But it showing "Exception in thread "main" java.lang.NullPointerException at room.Test.main(Test.java:26)", below is my code for the test.java:

public class Test {

    public static void main(String[] args) {
        Room[] room = new Room[72];
        Integer i = 0;
        try {
            File RoomTxt = new File("Room.txt");
            Scanner read = new Scanner(RoomTxt);
            while (read.hasNextLine()) {
                room[i].setRoomID(read.next());
                room[i].setRoomType(read.next() + " " + read.next());
                room[i].setFloor(read.nextInt());
                room[i].setRoomStatus(read.nextInt());
                read.nextLine();
                i++;
            }
            read.close();
        } catch (FileNotFoundException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
}

Below is the class I used to store the Room type:

public class Room {

    private String roomID;
    private String roomType;
    private Integer floor;
    private Integer roomStatus;

    //Setter
    public void setRoomID(String roomID) {
        this.roomID = roomID;
    }

    public void setRoomType(String roomType) {
        this.roomType = roomType;
    }

    public void setFloor(Integer floor) {
        this.floor = floor;
    }

    public void setRoomStatus(Integer roomStatus) {
        this.roomStatus = roomStatus;
    }

    //Getter
    public String getRoomID() {
        return this.roomID;
    }

    public String getRoomType() {
        return this.roomType;
    }

    public Integer getFloor() {
        return this.floor;
    }

    public Integer getRoomStatus() {
        return this.roomStatus;
    }
}

PS. The records stored inside my Room.txt is like

RS11 Single Room 1 1
RD12 Double Room 1 0

Answer 1

You need to write room[I] = new Room(); before you start calling its setters.