public String createContainer(String sid, String cid) throws StorageCloudException {
try{
args.clear();
args.add(sid);
args.add(cid);
Message msg = new Message("createContainer", args, null);
out.writeObject(msg);
out.reset();
try {
msg = (Message) in.readObject();
if(msg.getOp().equals("ok")){
//System.out.println("Download executado com sucesso");
return cid;
}else{
//System.out.println("download com problemas");
throw new StorageCloudException("Container creation failed... maybe container already exist.");