update

edu-im/edu-im-server/src/main/java/com/keao/edu/im/service/Impl/RoomServiceImpl.java

@@ -97,7 +97,7 @@ public class RoomServiceImpl implements RoomService {
         }
     }*/
 
-    public void joinRoomSuccess(RoomMember roomMember) throws Exception {
+    public synchronized void joinRoomSuccess(RoomMember roomMember) throws Exception {
         String roomId = roomMember.getRid();
         String userId = roomMember.getUid();
         Long registrationId = roomMember.getExamRegistrationId();
@@ -129,7 +129,7 @@ public class RoomServiceImpl implements RoomService {
 
     @Override
     @Transactional(rollbackFor = Exception.class, isolation = Isolation.SERIALIZABLE)
-    public BaseResponse joinRoom(Long registrationId, String roomId){
+    public synchronized BaseResponse joinRoom(Long registrationId, String roomId){
         StudentExamApiDto examResult = null;
         log.info("joinRoom: roomId={}, registrationId={}", roomId,registrationId);