Java: NullPointerException when calling a method

Question

I'm currently writing a little game using an 2D Array (Array of Arrays). In one of my classes which is handling the movement and placement of enemy units, there is a method that calls upon a method called "getPos" this is the Array in which the position of all enemies are stored, however I'm encountering a NullPointerException and can't for the life of me spot why it's snagging there.

Below is the code the exception is flagged, I managed to pin the error on the line

"gridPos[0][0].getType()":

public class Movement extends ArrayControl {

public Movement(Display display) {
    super(display);
}

private static ArrayControl arrayControl = new ArrayControl(display);

public static void addEnemyShip(){
    EnemyBehaviour[][] gridPos = display.getGridPos();
    gridPos[0][0] = new Ship();
    arrayControl.updatePosition(gridPos[0][0].getType(), 0, 0);
}

And this is the segment that handles the actual passing of gridPos:

public EnemyBehaviour[][] getGridPos() {
    return gridPos;
}

And this is the getType() method in the super class of Ship()

public String getType() {
    return type;
}