Index: lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/IMessageDAO.java
===================================================================
diff -u -r2b4141f8f15fe552ea1ba29d0b302544943cb6b0 -r08fe875b45ad68995664f316c1ed602b30ca2f42
--- lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/IMessageDAO.java	(.../IMessageDAO.java)	(revision 2b4141f8f15fe552ea1ba29d0b302544943cb6b0)
+++ lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/IMessageDAO.java	(.../IMessageDAO.java)	(revision 08fe875b45ad68995664f316c1ed602b30ca2f42)
@@ -10,6 +10,8 @@
 
     void update(Message message);
 
+    Message getByIdForUpdate(Long messageId);
+    
     Message getById(Long messageId);
 
     /**
Index: lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/hibernate/MessageDao.java
===================================================================
diff -u -r2b4141f8f15fe552ea1ba29d0b302544943cb6b0 -r08fe875b45ad68995664f316c1ed602b30ca2f42
--- lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/hibernate/MessageDao.java	(.../MessageDao.java)	(revision 2b4141f8f15fe552ea1ba29d0b302544943cb6b0)
+++ lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/persistence/hibernate/MessageDao.java	(.../MessageDao.java)	(revision 08fe875b45ad68995664f316c1ed602b30ca2f42)
@@ -27,6 +27,7 @@
 
 import java.util.List;
 
+import org.hibernate.LockOptions;
 import org.lamsfoundation.lams.dao.hibernate.LAMSBaseDAO;
 import org.lamsfoundation.lams.tool.forum.persistence.IMessageDAO;
 import org.lamsfoundation.lams.tool.forum.persistence.Message;
@@ -66,6 +67,11 @@
     }
 
     @Override
+	public Message getByIdForUpdate(Long messageId) {
+    	return (Message) getSession().get(Message.class, messageId, LockOptions.UPGRADE);
+	}
+
+    @Override
     public Message getById(Long messageId) {
 	return (Message) getSession().get(Message.class, messageId);
     }
Index: lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/service/ForumService.java
===================================================================
diff -u -r2b4141f8f15fe552ea1ba29d0b302544943cb6b0 -r08fe875b45ad68995664f316c1ed602b30ca2f42
--- lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/service/ForumService.java	(.../ForumService.java)	(revision 2b4141f8f15fe552ea1ba29d0b302544943cb6b0)
+++ lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/service/ForumService.java	(.../ForumService.java)	(revision 08fe875b45ad68995664f316c1ed602b30ca2f42)
@@ -299,6 +299,10 @@
 	return message;
     }
 
+    private Message getMessageForUpdate(Long messageUid) throws PersistenceException {
+    	return messageDao.getByIdForUpdate(messageUid);
+    }
+    
     public Message getMessage(Long messageUid) throws PersistenceException {
 	return messageDao.getById(messageUid);
     }
@@ -333,7 +337,7 @@
     @Override
     public Message replyTopic(Long parentId, Long sessionId, Message replyMessage) throws PersistenceException {
 	// set parent
-	Message parent = this.getMessage(parentId);
+	Message parent = this.getMessageForUpdate(parentId);
 	replyMessage.setParent(parent);
 	replyMessage.setForum(parent.getForum());
 	// parent sessionID maybe empty if created by author role. So given sessionId is exactly value.
Index: lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/web/actions/LearningAction.java
===================================================================
diff -u -rac12c171d18673d283c3304f1333ebb00e3819d0 -r08fe875b45ad68995664f316c1ed602b30ca2f42
--- lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/web/actions/LearningAction.java	(.../LearningAction.java)	(revision ac12c171d18673d283c3304f1333ebb00e3819d0)
+++ lams_tool_forum/src/java/org/lamsfoundation/lams/tool/forum/web/actions/LearningAction.java	(.../LearningAction.java)	(revision 08fe875b45ad68995664f316c1ed602b30ca2f42)
@@ -661,7 +661,7 @@
      * @return
      * @throws InterruptedException
      */
-    private synchronized ActionForward replyTopic(ActionMapping mapping, ActionForm form, HttpServletRequest request,
+    private ActionForward replyTopic(ActionMapping mapping, ActionForm form, HttpServletRequest request,
 	    HttpServletResponse response) throws InterruptedException {
 
 	MessageForm messageForm = (MessageForm) form;