diff --git a/backend/src/main/java/com/designhub/service/TaskProgressSnapshotService.java b/backend/src/main/java/com/designhub/service/TaskProgressSnapshotService.java
index d1d1e1d..41ffa0b 100644
--- a/backend/src/main/java/com/designhub/service/TaskProgressSnapshotService.java
+++ b/backend/src/main/java/com/designhub/service/TaskProgressSnapshotService.java
@@ -116,7 +116,7 @@ public class TaskProgressSnapshotService {
 
     private Map<Long, User> loadUsers(List<Task> tasks) {
         Set<Long> userIds = tasks.stream()
-            .flatMap(task -> List.of(task.getPublisherId(), task.getReceiverId()).stream())
+            .flatMap(task -> java.util.stream.Stream.of(task.getPublisherId(), task.getReceiverId()))
             .filter(Objects::nonNull)
             .collect(Collectors.toSet());
         if (CollectionUtils.isEmpty(userIds)) {
@@ -128,7 +128,7 @@ public class TaskProgressSnapshotService {
 
     private Map<Long, Department> loadDepartments(List<Task> tasks) {
         Set<Long> deptIds = tasks.stream()
-            .flatMap(task -> List.of(task.getReceiverDeptId(), task.getPublisherDeptId()).stream())
+            .flatMap(task -> java.util.stream.Stream.of(task.getReceiverDeptId(), task.getPublisherDeptId()))
             .filter(Objects::nonNull)
             .collect(Collectors.toSet());
         if (CollectionUtils.isEmpty(deptIds)) {