docs: @Override
      public int compare(final Issue i1, final Issue i2) {
  
          if (null == i1 && null == i2) {
              return 0;
          } else if (null == i1) {
              return 1;
          } else if (null == i2) {
              return -1;
          } else {
              return i1.getCreatedOn().compareTo(i2.getCreatedOn());
          }
      }