Write list of doubles to file

I have an arraylist of doubles that I update each time I iterate through an algorithm. I want to output the full list of numbers to a file but it as only outputting one value instead of the entire list. I use a simple simulated annealing local search. After each evaluation I store the new value in an array and I want to then output all values of the list to a file.

My code:

        while (eval < 50) {
            //Pick two positions on the grid
            int Pos1 = (int) (Math.random() * size());
            int Pos2 = (int) (Math.random() * size());


            boolean swap = array1[Pos1];
            array2[Pos1] = array1[Pos2];
            array2[Pos2] = swap;


            Fitness = evaluate(array2);
            double current = fits[value];
            System.out.println(eval + " " +Fitness);
            list = Arrays.asList(Fitness);
            //I WANT TO SAVE ALL VALUES IN THIS LIST TO A FILE



            //Keep track of best solution by only replacing it if a better fitness
            //value is found by the algorithm
            if(Fitness <= current)
            {
                for(int i=0; i<grid.size();i++) {
                    individuals[value][i] = array2[i];
                    fits[value] = Fitness;
                } 

            }
            else {
                //value for the current solution
                double difference = Fitness - current;
                double random = Math.random();
                double prob = Math.exp(-(double)Math.abs(difference)/Temp);


                if(prob > random)
                {
                    for(int i=0; i<grid.size();i++) {
                        individuals[value][i] = array1[i];
                        fits[value] = current;
                    }

                }
            }

            //Cool the system
            Temp *= 1-coolingRate;
            eval++;
        }

Code that writes only one entry to file:

    list = Arrays.asList(Fitness);

    try (BufferedWriter bw = new BufferedWriter(new FileWriter(FNAME))) {
        for (Double line : list) {
            bw.write(line + "\n");
        }
        bw.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

Implementation used to write Array of doubles to file:

ArrayList<Double> yourArray = new ArrayList<>();
final String FILENAME = "sample.txt";
            list.add(arrayValue)
            try ( BufferedWriter bw = new BufferedWriter (new FileWriter (FILENAME)) ) 
            {           
                for (Double line : yourArray) {
                    bw.write (line + "\n");
                    bw.newLine();
                }

                bw.close ();

            } catch (IOException e) {
                e.printStackTrace ();
            }