// get the response and set header info var response = facesContext.getExternalContext().getResponse();; response.setContentType("application/json"); response.setHeader("Cache-Control", "no-cache"); // get the output writer and print the data var pageOut = facesContext.getResponseWriter(); pageOut.write("{'jsonvar'='jsonvalue'"); pageOut.endDocument(); pageOut.close(); facesContext.responseComplete();