Program: 98706
Project: 98706
Buggy source:
@Override public void processPacket(Packet packet){
  if (packet instanceof Message) {
    Message msg=(Message)packet;
    String body=msg.getBody();
    String sender=msg.getFrom();
    Occupant oc=chatRoom.getOccupant(sender);
    if (!oc.getNick().equals(chatRoom.getNickname())) {
      if (body.startsWith(Constants.PREFIX_COMMAND)) {
        String cmd=body.substring(Constants.PREFIX_COMMAND.length()).split("String_Node_Str")[0].trim();
        if (cmd.equalsIgnoreCase(Constants.COMMAND_ONLINEPLAYERS)) {
          try {
            if (plugin.getServer().getOnlinePlayers().length != 0) {
              String players="String_Node_Str";
              for (              Player player : plugin.getServer().getOnlinePlayers()) {
                players+=player.getDisplayName() + "String_Node_Str";
              }
              chatRoom.sendMessage(String.format(Constants.TEXT_ONLINE_PLAYERS + players.trim(),plugin.getServer().getOnlinePlayers().length));
            }
 else {
              chatRoom.sendMessage(Constants.TEXT_ONLINE_NONE);
            }
          }
 catch (          XMPPException ex) {
            log.log(Level.SEVERE,Constants.PREFIX_LOG + "String_Node_Str",ex);
          }
        }
 else {
          if ((oc.getRole().equalsIgnoreCase("String_Node_Str")) || (oc.getRole().equalsIgnoreCase("String_Node_Str"))) {
            String command=body.substring(Constants.PREFIX_COMMAND.length()).trim();
            boolean executed=Bukkit.dispatchCommand(Bukkit.getConsoleSender(),command);
            try {
              if (!executed) {
                chatRoom.sendMessage(String.format(Constants.TEXT_COMMAND_IMPOSSIBLE,command));
              }
            }
 catch (            XMPPException ex) {
              log.log(Level.SEVERE,Constants.PREFIX_LOG + "String_Node_Str",ex);
            }
          }
        }
      }
 else {
        plugin.broadcast(oc.getNick() + "String_Node_Str" + body);
      }
    }
  }
}

Fixed version (ground truth):
@Override public void processPacket(Packet packet){
  if (packet instanceof Message) {
    Message msg=(Message)packet;
    String body=msg.getBody();
    String sender=msg.getFrom();
    Occupant oc=chatRoom.getOccupant(sender);
    if (!oc.getNick().equals(chatRoom.getNickname())) {
      if (body.startsWith(Constants.PREFIX_COMMAND)) {
        String cmd=body.substring(Constants.PREFIX_COMMAND.length()).split("String_Node_Str")[0].trim();
        if (cmd.equalsIgnoreCase(Constants.COMMAND_ONLINEPLAYERS)) {
          try {
            if (plugin.getServer().getOnlinePlayers().length != 0) {
              String players="String_Node_Str";
              for (              Player player : plugin.getServer().getOnlinePlayers()) {
                players+=player.getDisplayName() + "String_Node_Str";
              }
              chatRoom.sendMessage(String.format(Constants.TEXT_ONLINE_PLAYERS + players.trim(),plugin.getServer().getOnlinePlayers().length));
            }
 else {
              chatRoom.sendMessage(Constants.TEXT_ONLINE_NONE);
            }
          }
 catch (          XMPPException ex) {
            log.log(Level.SEVERE,Constants.PREFIX_LOG + "String_Node_Str",ex);
          }
        }
 else {
          if ((oc.getRole().equalsIgnoreCase("String_Node_Str")) || (oc.getRole().equalsIgnoreCase("String_Node_Str"))) {
            String command=body.substring(Constants.PREFIX_COMMAND.length()).trim();
            boolean executed=plugin.getServer().dispatchCommand(plugin.getServer().getConsoleSender(),command);
            try {
              if (!executed) {
                chatRoom.sendMessage(String.format(Constants.TEXT_COMMAND_IMPOSSIBLE,command));
              }
            }
 catch (            XMPPException ex) {
              log.log(Level.SEVERE,Constants.PREFIX_LOG + "String_Node_Str",ex);
            }
          }
        }
      }
 else {
        plugin.broadcast(oc.getNick() + "String_Node_Str" + body);
      }
    }
  }
}