[JAVA-12943] Improvement

libraries-http/src/main/java/com/baeldung/javalin/User/User.java

@@ -1,5 +1,5 @@
 package com.baeldung.javalin.User;
-import com.fasterxml.jackson.annotation.JsonProperty;
+
 
 public class User {
     public int id;

libraries-http/src/main/java/com/baeldung/javalin/User/UserController.java

@@ -3,6 +3,7 @@ package com.baeldung.javalin.User;
 import io.javalin.Handler;
 
 import java.util.Objects;
+import java.util.Optional;
 
 public class UserController {
     public static Handler fetchAllUsernames = ctx -> {
@@ -14,11 +15,11 @@ public class UserController {
     public static Handler fetchById = ctx -> {
         int id = Integer.parseInt(Objects.requireNonNull(ctx.param("id")));
         UserDao dao = UserDao.instance();
-        User user = dao.getUserById(id).get();
-        if (user == null) {
-            ctx.html("Not Found");
-        } else {
+        Optional<User> user = dao.getUserById(id);
+        if(user.isPresent()){
             ctx.json(user);
+        } else {
+            ctx.html("User Not Found");
         }
     };
 }