title: Get the number of weeks between two Dates.
body: <p>Im working in a project and I got two types in Date. I want to calculate the number of weeks between these two dates. The dates can be in diffrent years. Is there any good solution for this? </p>
  
  <p>I have tried to implemenent this with Joda-time which was suggested in other topics.. </p>
  
  <p>Im not familar with this library, but I tried to do something like this:</p>
  
  <pre><code>public static int getNumberOfWeeks(Date f, Date l){
      Calendar c1 = Calendar.getInstance();
      Calendar c2 = Calendar.getInstance();
      c1.setTime(f);
      c2.setTime(l);
      DateTime start = new DateTime(c1.YEAR, c1.MONTH, c1.DAY_OF_MONTH, 0, 0, 0, 0);
      DateTime end   = new DateTime(c2.YEAR, c2.MONTH, c2.DAY_OF_MONTH, 0, 0, 0, 0);
      Interval interval = new Interval(start, end);
      Period p = interval.toPeriod();
      return p.getWeeks();
  }
  </code></pre>
  
  <p>But this is completely wrong... any suggestions ? </p>