Question

So I have a method to write a string to a file:

 public static void saveStringToFile(String path, String string) {

    File file = new File(path);
    if (!file.exists()) {
        try {
            file.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();

        }
    }

    FileWriter out = null;
    try {
        out = new FileWriter(path);
        out.write(string);
        if (out != null) {
            out.close();
        }
    } catch (FileNotFoundException e) {

        e.printStackTrace();

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

}

And my test class with the following setUp method which runs before each test (to delete the testfile before each one):

public static final String TEST_FILE = "somefile.xml";

//…

@Before
public void setUp() throws IOException {
    if (MyCustomClass.fileExists(TEST_FILE)) {
        new File(TEST_FILE).delete();
    }
}

Each of my test tries to write something to the file using the method saveStringToFile(). It succeeds like for a couple of times, but a some random point I finally get the java.io.IOException: Access is denied. Got no idea why this happens – sometimes it occurs in test1, sometimes in test3…

It was working OK, when I was using Java7 FileIO, but I needed to migrate back to Java6…

Answer 1

So, probably JUnit wasn’t running it parrallel, cause as I suppose It doesn’t do it by default.

The problem was in my readfile method:

private String readFile(String path) throws FileNotFoundException {
    return (new Scanner(new File(path))).useDelimiter("\\Z").next();
}

To work fine I had to fix

private String readFile(String path) throws FileNotFoundException {
    Scanner scanner = (new Scanner(new File(path)));
    String s = scanner.useDelimiter("\\Z").next();
    scanner.close();
    return s;
}

The close() method for Scanner was the key…