If a student has a reason to hand in an archived answer instead of learning something by solving the problem himself, there's already something going wrong, and

If a student has a reason to hand in an archived answer instead of learning something by solving the problem himself, there's already something going wrong, and creating fresh exercises each week attacks a symptom only. Why do students use archived answers in the first place? Apparently, to get credits for (and ultimately pass) a course whose course points they need for something but whose contents they don't want to learn that badly that investing their own time would seem worthwhile. I see two ways in which to attack this situation: 1. Remove the possibility of passing a course without having understood its contents: e.g. oral exams with "why" questions. 2. Remove the perceived necessity to get a good grade: on the small scale, the easier it is to cheat in a single test, the less it should contribute to the grade. On the larger scale, perhaps curriculae need to be more diverse such that a "I just want to be a Java programmer with a degree such that I earn more money" student can become "just a Java programmer with a degree in just Java".