public class DocumentationController {
@GET
@Path("/doc")
public static Object get(Response response,Request request) throws Exception{
    String path = "/apps/static/doc/";
    String fileName = "api.html";

    File file = new File(path + fileName);

    String htmlContent = null;
    try {
        htmlContent = Files.asCharSource(file, Charsets.UTF_8).read();
    } catch (IOException e) {
        throw new Exception(e.getMessage());
    }
    response.status(HttpServletResponse.SC_OK);
    request.header("Content-Type", MediaType.HTML_UTF_8.toString());

    return htmlContent;
}