code: public static IRing getHeaviestRing(IRingSet ringSet, IBond bond) {
          IRingSet rings = ringSet.getRings(bond);
          IRing ring = null;
          int maxOrderSum = 0;
          for (Object ring1 : rings.atomContainers()) {
              if (maxOrderSum < ((IRing) ring1).getBondOrderSum()) {
                  ring = (IRing) ring1;
                  maxOrderSum = ring.getBondOrderSum();
              }
          }
          return ring;
      }
docs: We define the heaviest ring as the one with the highest number of double bonds.
  Needed for example for the placement of in-ring double bonds.
  
  @param ringSet The collection of rings
  @param   bond  A bond which must be contained by the heaviest ring
  @return  The ring with the higest number of double bonds connected to a given bond