code: public final synchronized Link getNextLink(Link after) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.entry(this, tc, "getNextLink", after);
          }
          Link replyLink = null;
          if (null == after) {
              replyLink = _dummyHead.getNextPhysicalLink();
          } else {
              replyLink = after.getNextPhysicalLink();
          }
          while (null != replyLink && replyLink.isLogicallyUnlinked()) {
              replyLink = replyLink.getNextPhysicalLink();
          }
          if (_dummyTail == replyLink) {
              replyLink = null;
          }
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.exit(this, tc, "getNextLink", replyLink);
          }
          return replyLink;
      }
docs: Reply the next (valid) link after the specified link. If the specified
  link is null then start at beginning of list.
  @param after
  @return