NullPointerException error when attempting to iterate through an ArrayList

Question

I am trying to make a class which will generate ArrayLists that will be called and iterated on a different class. I'm afraid i have a problem into how the ArrayLists were made or how i'm attempting to call the ArrayList into a different class. Program crashes when a PinballObject hits the assigned left wall.

java.lang.NullPointerException at PinballObject.move(PinballObject.java:85)

"for(PinballObject po : objectlist.getPinballTypeOneList())"

    public class PinballObject
{
    private int currentXLocation;
    private int currentYLocation;
    private int speedXTravel;
    private int speedYTravel;
    private Color colour;
    private int radius;
    private Machine machine;
    private ObjectList objectlist;
    private final int leftWallPosition;
    private final int bottomWallPosition;
    private final int topWallPosition;
    private final int rightWallPosition;






    /**
     * Constructor for objects of class Pinball_Obj
     * 
     * @param xPos  the horizontal coordinate of the object
     * @param yPos  the vertical coordinate of the object
     * @param xVel  the horizontal speed of the object
     * @param yVel  the vertical speed of the object
     * @param objectRadius  the radius (in pixels) of the object
     * @param objectColor  the color of the object
     * @param theMachine  the machine this object is in
     */
    public PinballObject(int xPos, int yPos, int xVel, int yVel, Color objectColor, int objectRadius, Machine theMachine)
    {
        currentXLocation = xPos;
        currentYLocation = yPos;
        speedXTravel = xVel;
        speedYTravel = yVel;
        colour = objectColor;
        radius = objectRadius;
        machine = theMachine;
        leftWallPosition = machine.getLeftWall();
        bottomWallPosition = machine.getBottomWall();
        topWallPosition = machine.getTopWall();
        rightWallPosition = machine.getRightWall();
    }



    /**
     * Move this object according to its position and speed and redraw.
     **/
    public void move()
    {
         // remove from universe at the current position
        machine.erase(this);
        // compute new position
        currentYLocation += speedYTravel;
        currentXLocation += speedXTravel;

        // check if it has hit the leftwall 
        if(currentXLocation <= (leftWallPosition + radius)) 
        {
            currentXLocation = leftWallPosition + radius;
            speedXTravel = -speedXTravel;

            for(PinballObject po : objectlist.getPinballTypeOneList())
            {
                if(this.equals(po))
                {
                    colour = Color.ORANGE;
                }
            }


        }

        machine.draw(this);
    }

You will find the ObjectList class as well below.

    public class ObjectList
{
    private PinballObject pinballobject;
    private Machine machine;

    private ArrayList<PinballObject> pinballTypeOneList = new ArrayList<PinballObject>();
    private ArrayList<PinballObject> pinballTypeTwoList = new ArrayList<PinballObject>();
    private ArrayList<PinballObject> bumperList = new ArrayList<PinballObject>();


    PinballObject firstTypeOne = new PinballObject(50, 200, -5, 3, Color.RED, 10, machine);
    PinballObject secondTypeOne = new PinballObject(100, 300, 1, 2, Color.BLUE, 55, machine); 
    PinballObject thirdTypeOne = new PinballObject(450, 125, -1, -1, Color.YELLOW, 40, machine);

    PinballObject firstTypeTwo = new PinballObject(200, 50, 3, -5, Color.MAGENTA, 25, machine);
    PinballObject secondTypeTwo = new PinballObject(300, 100, 2, -1, Color.PINK, 45, machine);
    PinballObject thirdTypeTwo = new PinballObject(250, 250, 4, -2, Color.GREEN, 30, machine);

    PinballObject firstBumper = new PinballObject(120, 135, 0, 0, Color.GRAY, 23, machine);
    PinballObject secondBumper = new PinballObject(344, 400, 0, 0, Color.GRAY, 13, machine);

    public void main(String[] args)
    {
        collection();
    }

    public void collection()
    {
        pinballTypeOneList.add(firstTypeOne);
        pinballTypeOneList.add(firstTypeOne);
        pinballTypeOneList.add(firstTypeOne);

        pinballTypeTwoList.add(firstTypeTwo);
        pinballTypeTwoList.add(secondTypeTwo);
        pinballTypeTwoList.add(thirdTypeTwo);

        bumperList.add(firstBumper);
        bumperList.add(secondBumper);

    }

    public ArrayList<PinballObject> getPinballTypeOneList()
    {
        return pinballTypeOneList;
    }

    public ArrayList<PinballObject> getPinballTypeTwoList()
    {
        return pinballTypeTwoList;
    }

    public ArrayList<PinballObject> getBumpers()
    {
        return bumperList;
    }
}

I think it's because the iteration is finding 0 stored objects within the ArrayList or perhaps how i'm trying to implemented these ArrayLists. I have read through what is a NullPointerException and how to fix it but i still can't pull through.

Any answer/suggestion will be more than welcome, i will be active with replies and i hope this case can help other learning coders in the future.