This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
So what exactly is your problem?
One thing I have noticed is you haven't shown any code to move the x,y position of the bullet every n milliseconds. BTW to do this your bullet class will need to know what direction the bullet is traveling in unless you can only fire in one direction. You may also want to record velocity and/or distance traveled unless your bullets go forever at the same speed.
Never use == true and == false. Why is the List inside the Bullet class? Do bullets hold information about other bullets in real life? I think that List belongs inside a different class, maybe Magazine or Bandolier.