code: public void apply(FaceletContext ctx, UIComponent parent) throws IOException, FacesException, FaceletException,
              ELException
      {
          UIViewRoot root = ComponentSupport.getViewRoot(ctx, parent);
          ResourceBundle bundle = null;
          try
          {
              String name = this.basename.getValue(ctx);
              ClassLoader cl = ClassUtils.getContextClassLoader();
              if (root != null && root.getLocale() != null)
              {
                  bundle = ResourceBundle.getBundle(name, root.getLocale(), cl);
              }
              else
              {
                  bundle = ResourceBundle.getBundle(name, Locale.getDefault(), cl);
              }
          }
          catch (Exception e)
          {
              throw new TagAttributeException(this.tag, this.basename, e);
          }
          ResourceBundleMap map = new ResourceBundleMap(bundle);
          FacesContext faces = ctx.getFacesContext();
          faces.getExternalContext().getRequestMap().put(this.var.getValue(ctx), map);
      }
docs: See taglib documentation.
  
  @see javax.faces.view.facelets.FaceletHandler#apply(javax.faces.view.facelets.FaceletContext, javax.faces.component.UIComponent)