code: public static void addCacheEntry(final ClassLoader classLoader, final String factoryId, final String factoryClassName) {
          if (factoryClassName == null) {
              CLASS_CACHE.put(new CacheKey(classLoader, factoryId), "");
          } else {
              CLASS_CACHE.put(new CacheKey(classLoader, factoryId), factoryClassName);
          }
      }
docs: Called by the container at deployment time to set the name of a given factory, to remove the need for the
  implementation to look it up on every call.
  
  @param classLoader      The deployments class loader
  @param factoryId        The type of factory that is being recorded (at this stage only javax.el.ExpressionFactory has any effect
  @param factoryClassName The name of the factory class that is present in the deployment, or null if none is present