How to write or store string array in .txt file in java

Question

I want to write string array in .txt file. But after running my code, I am getting an empty file. Here is my code.

public void DataSave() throws IOException {
        File fout = new File("Data.txt");
        FileOutputStream fos = new FileOutputStream(fout);

        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));

        String[] numberOfProperty = new String[3];
        numberOfProperty[0] = "1";
        numberOfProperty[1] = "3";
        numberOfProperty[2] = "4";
        for (int i = 0; i < numberOfProperty.length; i++) {
            bw.write(numberOfProperty[i]);
            bw.newLine();
        }
    }

What's wrong in my code I cannot understand.Compiler shows no error. Please Help. All answer would be appreciated.

Answer 1

public void DataSave() {
    File fout = new File("Data.txt");
    try (FileOutputStream fos = new FileOutputStream(fout); BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));) {
        String[] numberOfProperty = new String[3];
        numberOfProperty[0] = "1";
        numberOfProperty[1] = "3";
        numberOfProperty[2] = "4";
        for (String s : numberOfProperty) {
            bw.write(s);
            bw.newLine();
        }
    } catch (IOException ignored) {

    }
}

You need to close the BufferedReader. A better solution is using try-with-resources, so you don't need to worry about closing.

You can have multiple resources in the try-with-resources separated by a ;.

---

Java 13+, you can use Path.of():

public void DataSave() {
    File fout = new File("Data.txt");
    try (FileOutputStream fos = new FileOutputStream(fout); BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));) {
        String[] numberOfProperty = new String[3];
        numberOfProperty[0] = "1";
        numberOfProperty[1] = "3";
        numberOfProperty[2] = "4";
        Files.write(Path.of("Data.txt"), Collections.singletonList(numberOfProperty));
    } catch (IOException ignored) {

    }
}

---

You can also write your array in one line as:

String[] numberOfProperty = {"1", "2", "3"};