title: How to apply overconstrained planning in OptaPlanner in a better way?
body: <p>In meeting scheduling example I'm trying to apply overconstrained planning. I've checked documentation and also answers in stackoverflow, then applied <strong>nullable = true</strong> to the @PlanningVariable which is in the MeetingAssignment:</p>
  
  <pre><code>   @PlanningVariable(valueRangeProviderRefs = { "roomRange" }, nullable = true)
     public Room getRoom() {
        return room;
     }
  </code></pre>
  
  <p>Also I've added a rule to the drool:</p>
  
  <pre><code>rule "Assign Every Person To A Room"
      when
          $meetingAssignment : MeetingAssignment(room == null)
      then
          scoreHolder.addMediumConstraintMatch(kcontext, -100);
  end
  </code></pre>
  
  <p>My scoreholder is: <strong>HardMediumSoftScoreHolder</strong></p>
  
  <p>However when I run the application, only one person out of six different person can be assigned. This doesn't occure if nullable is false and every person can be assigned. Also this six person doens't break hard constraint.
  Do you have any idea for overconstraint planning solution problem?</p>
  
  <p>Thank you!</p>