Dragging a JPanel using MouseMotionListener

Question

I'm making a program where the user will drag a card across a table using the mouse. The Card is a JPanel and so is Table. Table has a null layout. In the Card class, I have this:

@Override
public void mouseDragged(MouseEvent e) 
{
    if (this.getWhere() == 1) // makes sure the card is on the table
    {

        Table.table.moveCard(this, e.getX(), e.getY());
    }
}

Then in the Table class:

public void moveCard(Card card, int x, int y)
{
    card.setLocation(x, y);
}

When I drag the card, it will jump back and forth from where the mouse is and a point near the top left corner of the panel.

Any help?