code: boolean isValidCopy(BackedSession sess, long nowTime, int versionId) {
          synchronized (sess) {
              if (!sess.isValid())
                  return false;
  
              int maxTime = sess.getMaxInactiveInterval();
              boolean accBeforeTO = (sess.getCurrentAccessTime() >= nowTime - (1000 * (long) maxTime));//PK90548
              boolean cacheIdMatch = (sess.getVersion() >= versionId);
  
              return (cacheIdMatch && (accBeforeTO || maxTime == -1));
          }
      }
docs: /*
  isValidCopy - determines if the cached session is still valid