servlet-vs-jaxrs.json

{
  "id": 98,
  "slug": "servlet-vs-jaxrs",
  "title": "Servlet versus JAX-RS",
  "category": "enterprise",
  "difficulty": "intermediate",
  "jdkVersion": "11",
  "oldLabel": "Java EE",
  "modernLabel": "Jakarta EE 8+",
  "oldApproach": "HttpServlet",
  "modernApproach": "JAX-RS Resource",
  "oldCode": "@WebServlet(\"/users\")\npublic class UserServlet extends HttpServlet {\n    @Override\n    protected void doGet(HttpServletRequest req,\n                         HttpServletResponse res)\n            throws ServletException, IOException {\n        String id = req.getParameter(\"id\");\n        res.setContentType(\"application/json\");\n        res.getWriter().write(\"{\\\"id\\\":\\\"\" + id + \"\\\"}\");\n    }\n}",
  "modernCode": "@Path(\"/users\")\npublic class UserResource {\n    @GET\n    @Produces(MediaType.APPLICATION_JSON)\n    public Response getUser(\n            @QueryParam(\"id\") String id) {\n        return Response.ok(new User(id)).build();\n    }\n}",
  "summary": "Replace verbose HttpServlet boilerplate with declarative JAX-RS resource classes.",
  "explanation": "JAX-RS (Jakarta RESTful Web Services) lets you expose REST endpoints using simple annotations like @GET, @Path, and @Produces. No more manual parsing of request parameters or setting content types on the response — the runtime handles marshalling and routing automatically.",
  "whyModernWins": [
    {
      "icon": "📐",
      "title": "Declarative routing",
      "desc": "Annotations define HTTP method, path, and content type instead of imperative if/else dispatch."
    },
    {
      "icon": "🔄",
      "title": "Automatic marshalling",
      "desc": "Return POJOs directly; the runtime serialises them to JSON or XML based on @Produces."
    },
    {
      "icon": "🧪",
      "title": "Easier testing",
      "desc": "Resource classes are plain Java objects, testable without a servlet container."
    }
  ],
  "support": {
    "state": "available",
    "description": "Widely available since Jakarta EE 8 / Java 11"
  },
  "prev": "language/compact-canonical-constructor",
  "next": "enterprise/ejb-vs-cdi",
  "related": [
    "enterprise/ejb-vs-cdi",
    "enterprise/jdbc-vs-jpa",
    "io/http-client"
  ],
  "docs": [
    {
      "title": "Jakarta RESTful Web Services Specification",
      "href": "https://jakarta.ee/specifications/restful-ws/"
    },
    {
      "title": "Jakarta REST 3.1 API",
      "href": "https://jakarta.ee/specifications/restful-ws/3.1/apidocs/"
    }
  ]
}