code: Object get(Class<?> type, Object key) {
          return map.get(new Key(type, key));
      }
docs: Returns the value from the cache with the given <code>type</code> and
  <code>key</code>.
  
  @param type the query type.
  @param key  the key object.
  @return the value assigned to <code>type</code> and <code>key</code> or
  <code>null</code> if it does not exist in the cache.