code: public final void setWrapFactory(WrapFactory wrapFactory)
      {
          if (sealed) onSealedMutation();
          if (wrapFactory == null) throw new IllegalArgumentException();
          this.wrapFactory = wrapFactory;
      }
docs: Set a WrapFactory for this Context.
  <p>
  The WrapFactory allows custom object wrapping behavior for
  Java object manipulated with JavaScript.
  @see WrapFactory
  @since 1.5 Release 4