code: public boolean stop() {
          if (scheduledFuture != null && !scheduledFuture.isCancelled()) {
              scheduledFuture.cancel(DO_NOT_INTERRUPT_IF_RUNNING);
              if (LOG.isDebugEnabled()) {
                  LOG.debug("{} Cache Manager stopped.", cache.getClass().getSimpleName());
              }
              return true;
          }
          return false;
      }
docs: Gracefully stop cacheManager.
  @return true if successfully cancel the scheduled future.