Null Object Reference

public class Card extends Sprite {
    // /////////////////////////////////////////////////////////////////////////
    // Variables
    // /////////////////////////////////////////////////////////////////////////


    //Card dimensions
    private static final float cardWidth = 195;
    private static final float cardHeight = 320;

    //Card parameters from CardInfo
    private int mID;                // Unique identification number of the card
    private Bitmap mCardImage;      // The image representing the card on the game board
    private String mName;           // The name of the hero presented on the card
    private Bitmap mDescription;    // The image containing the card's description
    private int mCost;              // The card's summon cost value
    private int mAttack;            // The card's attack value
    private int mHealth;            // The card's health value

    //Card's current bitmap
    private Bitmap mCardBase;

    //Card flipped status
    private boolean flipped;

    // Target for drag and drop
    private Vector2 moveTarget = new Vector2();
    // /////////////////////////////////////////////////////////////////////////
    // Constructors
    // /////////////////////////////////////////////////////////////////////////

    /**
     * Create a card
     *
     * @param startX     x location of the card
     * @param startY     y location of the card
     * @param width      Wdith of the card
     * @param height     Height of the card
     * @param gameScreen Gamescreen to which card belongs
     */
    public Card(float startX, float startY, float width, float height,  GameScreen gameScreen, CardInfo cardInfo) {
        super(startX, startY, width, height, cardInfo.getCardImage(), gameScreen);

        //AssetManager assetManager = gameScreen.getGame().getAssetManager();

        //Fill in parameters from cardInfo
        mID = cardInfo.getID();
        mCardImage = cardInfo.getCardImage();
        mName = cardInfo.getName();
        mDescription = cardInfo.getDescription();
        mCost = cardInfo.getCost();
        mAttack = cardInfo.getAttack();
        mHealth = cardInfo.getHealth();

        mCardBase = mCardImage;

        
        flipped = false;
    }

    // /////////////////////////////////////////////////////////////////////////
    // Methods
    // /////////////////////////////////////////////////////////////////////////


    /**
     * Draw the card
     *
     * @param elapsedTime    Elapsed time information
     * @param graphics2D     Graphics instance
     * @param layerViewport  Game layer viewport
     * @param screenViewport Screen viewport
     */
    @Override
    public void draw(ElapsedTime elapsedTime, IGraphics2D graphics2D,
                     LayerViewport layerViewport, ScreenViewport screenViewport) {

        // Draw the card base
        mBitmap = mCardBase;
        super.draw(elapsedTime, graphics2D, layerViewport, screenViewport);

    }

 // /////////////////////////////////////////////////////////////////////////
    // Variables
    // /////////////////////////////////////////////////////////////////////////

    private int mID;                // Unique identification number of the card
    private Bitmap mCardImage;      // The image representing the card on the game board
    private String mName;           // The name of the hero presented on the card
    private Bitmap mDescription;    // The image containing the card's description
    private int mCost;              // The card's summon cost value
    private int mAttack;            // The card's attack value
    private int mHealth;            // The card's health value

    // /////////////////////////////////////////////////////////////////////////
    // Constructors
    // /////////////////////////////////////////////////////////////////////////

    /**
     * Create a CardInfo object
     * @param ID
     * @param cardImage
     * @param name
     * @param description
     * @param cost
     * @param attack
     * @param health
     */
    public CardInfo(int ID, Bitmap cardImage, String name, Bitmap description, int cost, int attack, int health){

        // Fill in member variables based on the arguments passed in
        mID = ID;
        mCardImage = cardImage;
        mName = name;
        mDescription = description;
        mCost = cost;
        mAttack = attack;
        mHealth = health;

    }

    // /////////////////////////////////////////////////////////////////////////
    // Methods
    // /////////////////////////////////////////////////////////////////////////

    //Accessors

    public int getID(){
        return mID;
    }

    public Bitmap getCardImage(){
        return mCardImage;
    }

    public String getName(){
        return mName;
    }

    public Bitmap getDescription(){
        return mDescription;
    }

    public int getCost(){
        return mCost;
    }

    public int getAttack(){
        return mAttack;
    }

    public int getHealth(){
        return mHealth;
    }
}