Thank you everybody!

@Damocles:
Yes I use my own List implementation and what you mention did cross my mind this night. I'll test it right away.
Thank you!

@Kombucha: Thanks!

@Checkbutton: I could use the LinkedList Class of the java api, but I decided against it, as I could not find a way to really swap elements as most of the information of the LinkedList is hidden. But I'll check it out in the future.
Thank you.