changed java file

DemoApplication.java

@@ -1,13 +1,18 @@
-public class DemoApplication {
+import io.javalin.Javalin;
+import com.google.gson.Gson;
 
+public class DemoApplication {
     public static void main(String[] args) {
-        // Hugging Face provides the port via environment variable
-        int port = Integer.parseInt(System.getenv().getOrDefault("PORT", "8080"));
-
+        int port = 8080;
         Javalin app = Javalin.create().start(port);
 
+        Gson gson = new Gson();
+
+        app.get("/", ctx -> ctx.result("Hello from Javalin on Hugging Face!"));
+
         app.get("/user", ctx -> {
-            ctx.json(new User("Kevan", 21));
+            User user = new User("Kevan", 21);
+            ctx.result(gson.toJson(user));
         });
     }
 }

User.java

@@ -1,6 +1,6 @@
 public class User {
-    public String name;
-    public int age;
+    private String name;
+    private int age;
 
     public User(String name, int age) {
         this.name = name;