code: private ConfigurationContext getManagerContext(final CacheManager mgr) {
      ConfigurationContext ctx = manager2defaultConfig.get(mgr);
      if (ctx != null) {
        return ctx;
      }
      synchronized (this) {
        ctx = manager2defaultConfig.get(mgr);
        if (ctx != null) {
          return ctx;
        }
        if (mgr.isDefaultManager()) {
          ctx = classLoader2config.get(mgr.getClassLoader());
        }
        if (ctx == null) {
          ctx = createContext(mgr.getClassLoader(), mgr.getName(), getFileName(mgr));
        }
        Map<CacheManager, ConfigurationContext> m2 =
          new HashMap<CacheManager, ConfigurationContext>(manager2defaultConfig);
        m2.put(mgr, ctx);
        manager2defaultConfig = m2;
        return ctx;
      }
    }
docs: Hold the cache default configuration of a manager in a hash table. This is reused for all caches of
  one manager.