diff --git a/src/main/java/org/ntlab/tampoposerver/repositories/NotificationRepository.java b/src/main/java/org/ntlab/tampoposerver/repositories/NotificationRepository.java
index 0bc32e6..0c427de 100644
--- a/src/main/java/org/ntlab/tampoposerver/repositories/NotificationRepository.java
+++ b/src/main/java/org/ntlab/tampoposerver/repositories/NotificationRepository.java
@@ -3,21 +3,26 @@
 import org.ntlab.tampoposerver.models.Notification;
 import org.springframework.stereotype.Repository;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
+import java.util.*;
 
 @Repository
 public class NotificationRepository {
     private HashMap<String, HashMap<String, Notification>> notificationMap = new HashMap<>();
 
     //通知の追加
-    public Notification addNotification(String userId, String notificationId, String from, String text, String time) {
+    public Notification addNotification(String userId, String from, String text, String time) {
+        String notificationId;
+        Map<String, Notification> userNotifications = notificationMap.get(userId);
+        if (userNotifications == null) {
+            notificationId = Integer.toString(0);
+        }
+        else{
+            notificationId = Integer.toString(userNotifications.size());
+        }
+
         Notification n = new Notification(userId, notificationId, from, text, time);
 
-        if(notificationMap.get(userId) == null) {
+        if(userNotifications == null) {
             notificationMap.put(userId, new HashMap<>());
         }
         notificationMap.get(userId).put(notificationId, n);
@@ -40,8 +45,36 @@
             return new ArrayList<>();
         }
 
-        return userNotifications.values().stream()
-                .sorted((a, b) -> b.getTime().compareTo(a.getTime()))
-                .collect(Collectors.toList());
+        List<Notification> sortedNotifications = new ArrayList<>(userNotifications.values());
+
+        Collections.sort(sortedNotifications, new Comparator<Notification>() {
+            @Override
+            public int compare(Notification o1, Notification o2) {
+                if(o1.getTime().compareTo(o2.getTime()) < 0) {
+                    return 1;
+                }
+                else if(o1.getTime().compareTo(o2.getTime()) > 0) {
+                    return -1;
+                }
+                return 0;
+            }
+        });
+
+//        for(int i = 0; i < sortedNotifications.size() - 1; i++) {
+//            for(int j = i + 1; j < sortedNotifications.size(); j++) {
+//                if(sortedNotifications.get(i).getTime().compareTo(sortedNotifications.get(j).getTime()) < 0) {
+//                    Notification tmp = sortedNotifications.get(i);
+//                    sortedNotifications.set(i, sortedNotifications.get(j));
+//                    sortedNotifications.set(j, tmp);
+//                }
+//            }
+//        }
+
+        return sortedNotifications;
+
+//        ラムダ式
+//        return userNotifications.values().stream()
+//                .sorted((a, b) -> b.getTime().compareTo(a.getTime()))
+//                .collect(Collectors.toList());
     }
 }
diff --git a/src/test/java/org/ntlab/tampoposerver/repositories/NotificationRepositoryTest.java b/src/test/java/org/ntlab/tampoposerver/repositories/NotificationRepositoryTest.java
index 4f00ba7..2990edf 100644
--- a/src/test/java/org/ntlab/tampoposerver/repositories/NotificationRepositoryTest.java
+++ b/src/test/java/org/ntlab/tampoposerver/repositories/NotificationRepositoryTest.java
@@ -19,35 +19,39 @@
     void contextLoads() throws JsonProcessingException {
         NotificationRepository notificationRepository = new NotificationRepository();
 
-        Notification n1_1 = notificationRepository.addNotification("u01","n01","u00","telephone1","2025-06-10 10:00:11");
-        Notification n1_2 = notificationRepository.addNotification("u01","n02","u02","telephone2","2025-06-07 10:31:11");
-        Notification n1_3 = notificationRepository.addNotification("u01","n03","u02","telephone2","2025-06-07 12:09:22");
-        Notification n2 = notificationRepository.addNotification("u02","n01","u00","telephone3","2025-06-07 09:22:12");
+        Notification n1_1 = notificationRepository.addNotification("u01","u00","telephone1","2025-06-10 10:00:11");
+        Notification n1_2 = notificationRepository.addNotification("u01","u02","telephone2","2025-06-07 10:31:11");
+        Notification n1_3 = notificationRepository.addNotification("u01","u02","telephone2","2025-06-07 12:09:22");
+        Notification n2 = notificationRepository.addNotification("u02","u00","telephone3","2025-06-07 09:22:12");
 
-        Notification n = notificationRepository.getNotification("u01","n02");
+        Notification n = notificationRepository.getNotification("u01","1");
         assertEquals(n1_2.getText(),n.getText());
 
-        n = notificationRepository.getNotification("u01","n04");
+        n = notificationRepository.getNotification("u01","4");
         assertNull(n);
 
-        n = notificationRepository.getNotification("u03","n03");
+        n = notificationRepository.getNotification("u03","0");
         assertNull(n);
 
         System.out.println(notificationRepository.getNotificationsForUser("u01"));
+        List<Notification> sortednotifications = notificationRepository.getNotificationsForUser("u01");
+        for (Notification notification : sortednotifications) {
+            System.out.println("time:" + notification.getTime() + " nid:" + notification.getNotificationId());
+        }
 
-        System.out.println(notificationRepository.getNotification("u01","n01"));
+        System.out.println(notificationRepository.getNotification("u01","0"));
 
         //JSONに変換して表示するテスト
         ObjectMapper mapper = new ObjectMapper();
-        mapper.registerModule(new JavaTimeModule()); // LocalDateTime対応
-        mapper.findAndRegisterModules(); // 任意（自動登録）
+        mapper.registerModule(new JavaTimeModule());
+        mapper.findAndRegisterModules();
 
         List<Notification> notifications = notificationRepository.getNotificationsForUser("u01");
         String notificationsJson = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(notifications);
         System.out.println(notificationsJson);
 
         String singleNotificationJson = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(
-                notificationRepository.getNotification("u01", "n01")
+                notificationRepository.getNotification("u01", "1")
         );
         System.out.println(singleNotificationJson);
     }