Program: 104191
Project: 104191
Buggy source:
/** 
 * Process history messages.
 * @param historyList The collection of messages coming from history.
 * @param escapedMessageID The incoming message needed to be ignored ifcontained in history.
 */
public void processHistory(Collection<EventObject> historyList,String escapedMessageID){
  Iterator<EventObject> iterator=historyList.iterator();
  String historyString="String_Node_Str";
  String messageType;
  while (iterator.hasNext()) {
    Object o=iterator.next();
    if (o instanceof MessageDeliveredEvent) {
      MessageDeliveredEvent evt=(MessageDeliveredEvent)o;
      ProtocolProviderService protocolProvider=evt.getDestinationContact().getProtocolProvider();
      if (isGreyHistoryStyleDisabled(protocolProvider))       messageType=Constants.OUTGOING_MESSAGE;
 else       messageType=Constants.HISTORY_OUTGOING_MESSAGE;
      historyString+=processHistoryMessage(GuiActivator.getUIService().getMainFrame().getAccount(protocolProvider),evt.getTimestamp(),messageType,evt.getSourceMessage().getContent(),evt.getSourceMessage().getContentType());
    }
 else     if (o instanceof MessageReceivedEvent) {
      MessageReceivedEvent evt=(MessageReceivedEvent)o;
      ProtocolProviderService protocolProvider=evt.getSourceContact().getProtocolProvider();
      if (!evt.getSourceMessage().getMessageUID().equals(escapedMessageID)) {
        if (isGreyHistoryStyleDisabled(protocolProvider))         messageType=Constants.INCOMING_MESSAGE;
 else         messageType=Constants.HISTORY_INCOMING_MESSAGE;
        historyString+=processHistoryMessage(evt.getSourceContact().getDisplayName(),evt.getTimestamp(),messageType,evt.getSourceMessage().getContent(),evt.getSourceMessage().getContentType());
      }
    }
 else     if (o instanceof ChatRoomMessageDeliveredEvent) {
      ChatRoomMessageDeliveredEvent evt=(ChatRoomMessageDeliveredEvent)o;
      ProtocolProviderService protocolProvider=evt.getSourceChatRoom().getParentProvider();
      historyString+=processHistoryMessage(GuiActivator.getUIService().getMainFrame().getAccount(protocolProvider),evt.getTimestamp(),Constants.HISTORY_OUTGOING_MESSAGE,evt.getMessage().getContent(),evt.getMessage().getContentType());
    }
 else     if (o instanceof ChatRoomMessageReceivedEvent) {
      ChatRoomMessageReceivedEvent evt=(ChatRoomMessageReceivedEvent)o;
      if (!evt.getMessage().getMessageUID().equals(escapedMessageID)) {
        historyString+=processHistoryMessage(evt.getSourceChatRoomMember().getName(),evt.getTimestamp(),Constants.HISTORY_INCOMING_MESSAGE,evt.getMessage().getContent(),evt.getMessage().getContentType());
      }
    }
  }
  conversationPanel.insertMessageAfterStart(historyString);
  getChatWindow().getMainToolBar().changeHistoryButtonsState(this);
}

Fixed version (ground truth):
/** 
 * Process history messages.
 * @param historyList The collection of messages coming from history.
 * @param escapedMessageID The incoming message needed to be ignored ifcontained in history.
 */
public void processHistory(Collection<EventObject> historyList,String escapedMessageID){
  Iterator<EventObject> iterator=historyList.iterator();
  String messageType;
  while (iterator.hasNext()) {
    Object o=iterator.next();
    String historyString="String_Node_Str";
    if (o instanceof MessageDeliveredEvent) {
      MessageDeliveredEvent evt=(MessageDeliveredEvent)o;
      ProtocolProviderService protocolProvider=evt.getDestinationContact().getProtocolProvider();
      if (isGreyHistoryStyleDisabled(protocolProvider))       messageType=Constants.OUTGOING_MESSAGE;
 else       messageType=Constants.HISTORY_OUTGOING_MESSAGE;
      historyString=processHistoryMessage(GuiActivator.getUIService().getMainFrame().getAccount(protocolProvider),evt.getTimestamp(),messageType,evt.getSourceMessage().getContent(),evt.getSourceMessage().getContentType());
    }
 else     if (o instanceof MessageReceivedEvent) {
      MessageReceivedEvent evt=(MessageReceivedEvent)o;
      ProtocolProviderService protocolProvider=evt.getSourceContact().getProtocolProvider();
      if (!evt.getSourceMessage().getMessageUID().equals(escapedMessageID)) {
        if (isGreyHistoryStyleDisabled(protocolProvider))         messageType=Constants.INCOMING_MESSAGE;
 else         messageType=Constants.HISTORY_INCOMING_MESSAGE;
        historyString=processHistoryMessage(evt.getSourceContact().getDisplayName(),evt.getTimestamp(),messageType,evt.getSourceMessage().getContent(),evt.getSourceMessage().getContentType());
      }
    }
 else     if (o instanceof ChatRoomMessageDeliveredEvent) {
      ChatRoomMessageDeliveredEvent evt=(ChatRoomMessageDeliveredEvent)o;
      ProtocolProviderService protocolProvider=evt.getSourceChatRoom().getParentProvider();
      historyString=processHistoryMessage(GuiActivator.getUIService().getMainFrame().getAccount(protocolProvider),evt.getTimestamp(),Constants.HISTORY_OUTGOING_MESSAGE,evt.getMessage().getContent(),evt.getMessage().getContentType());
    }
 else     if (o instanceof ChatRoomMessageReceivedEvent) {
      ChatRoomMessageReceivedEvent evt=(ChatRoomMessageReceivedEvent)o;
      if (!evt.getMessage().getMessageUID().equals(escapedMessageID)) {
        historyString=processHistoryMessage(evt.getSourceChatRoomMember().getName(),evt.getTimestamp(),Constants.HISTORY_INCOMING_MESSAGE,evt.getMessage().getContent(),evt.getMessage().getContentType());
      }
    }
    conversationPanel.appendMessageToEnd(historyString);
  }
  getChatWindow().getMainToolBar().changeHistoryButtonsState(this);
}