code: private synchronized void checkCache()
      {
          Object[] pTables = m_setTableCacheList.toArray();
          for (Object objTable : pTables)
          {
              PTable pTable = (PTable)objTable;
              if (pTable.addPTableOwner(null) == 1)
              { // Not currently being used is a candidate for flushing from the cache.
                  long lTimeLastUsed = pTable.getLastUsed();
                  long lTimeCurrent = System.currentTimeMillis();
                  if ((lTimeCurrent - lTimeLastUsed) > (this.getCacheMinutes() * 60 * 1000))
                  {
                      pTable.removePTableOwner(this, true);
                      m_setTableCacheList.remove(pTable);
                  }
              }
          }
      }
docs: Check all the cached tables and flush the old ones.