code: @Override
      public int getUsedCacheSize() {
          DCache cache = null;
          if (ServerCache.servletCacheEnabled) {
              cache = ServerCache.cache;
          }
          int size = -1;
          if (cache != null) {
              size = cache.getNumberCacheEntries();
          } else {
              // DYNA1059W=DYNA1059W: WebSphere Dynamic Cache instance named {0} cannot be used because of Dynamic Servlet cache service has not be started.
              Tr.error(tc, "DYNA1059W", new Object[] { DCacheBase.DEFAULT_CACHE_NAME });
          }
          return size;
      }
docs: /*
  (non-Javadoc)
  
  @see com.ibm.websphere.cache.CacheAdminMBean#getUsedCacheSize()