Manipular arquivo pra somar valores iguais

try {
			FileReader fr = new FileReader(new File("C:\\Users\\kleber\\Desktop\\teste.txt"));
			BufferedReader  br = new BufferedReader(fr);
			
			TreeMap<String,Integer> aux = new TreeMap<String,Integer>();
			
			String linha = "";
			while((linha = br.readLine()) != "" && linha != null) {
				String[] valores = linha.split(" ");
				if(aux.get(valores[0]) == null) {
					aux.put(valores[0],Integer.parseInt(valores[1]));
				} else {
					aux.put(valores[0],aux.get(valores[0]) + Integer.parseInt(valores[1]));
				}
			}
			
			fr.close();
			BufferedWriter bw = new BufferedWriter(new FileWriter(new File("C:\\Users\\kleber\\Desktop\\teste.txt")));
			for (String codigo : aux.keySet()) {
				String qtd = aux.get(codigo).toString();
				bw.write(codigo + " " + qtd + "\r");
			}
			bw.close();
		} catch (Exception e) {
			e.printStackTrace();
		}