File is in use by another process but canRead() returns true

Question

I'm using another program to convert bin files to xml and then I'm trying to read the file. With the following code:

File file = new File(currentPath + "/ammunition.bin");
File file2 = fileTools.convert(file);
ArrayList<String> asd = fileTools.readFile(file2);

I get FileNotFoundException, "file is in use by another process". What makes this weird is that file.canRead() returns true even though i get the exception. Here is the rest of the code:

public ArrayList<String> readFile(File file) {

    ArrayList<String> result = new ArrayList<>();
    Scanner reader;
    try {
        reader = new Scanner(file, "UTF-8");
    } catch (FileNotFoundException ex) {
        boolean b = file.canRead();
        StringWriter errors = new StringWriter();
        ex.printStackTrace(new PrintWriter(errors));
        JOptionPane.showMessageDialog(null, errors.toString());
        alertError("readFile\n" + b + " " + ex.getMessage());
        return null;
    }
    while (reader.hasNext()) {
        result.add(reader.nextLine());
    }
    reader.close();
    return result;
}

public File changeFileExtension(File f, String ext) {
    String name = f.getAbsolutePath();
    int i = name.lastIndexOf(".");
    name = name.substring(0, i) + "." + ext;
    f = new File(name);
    return f;
}


public File convert(File file) {

    File binConverter = new File(this.currentPath + "\\GibbedsTools\\Gibbed.Avalanche.BinConvert.exe");

    if (!binConverter.exists()) {
        alertError("convert\nGibbedsTools is missing, it should be in\n" + this.currentPath + "\\GibbedsTools\\Gibbed.Avalanche.BinConvert.exe");
        return null;
    }

    if (!file.exists()) {
        alertError("convert\nFile does not exist\n" + file.getAbsolutePath());
    }

    String name = file.getName();
    String extension = name.substring(name.lastIndexOf(".") + 1, name.length());

    Runtime rt = Runtime.getRuntime();

    try {
        rt.exec("cmd.exe /c " + "\"\"" + this.currentPath + "\\GibbedsTools\\Gibbed.Avalanche.BinConvert.exe\" \"" + file.getAbsolutePath() + "\"\"");
    } catch (IOException ex) {
        alertError("binToXml\n" + ex.getMessage());
        return null;
    }

    File file2 = changeFileExtension(file, extension.equals("xml") ? "bin" : "xml");

    int timepassed = 0;

    while (!file2.exists() || !file2.canWrite() || timepassed <= 50) {
        try {
            Thread.sleep(50);
        } catch (InterruptedException ex) {
            alertError("binToXml\n" + ex.getMessage());
            return null;
        }
        timepassed += 50;
        if (timepassed > 3000) {
            if (!file2.exists()) {
                alertError("convert\nError, binconverter probably crashed (No xml file created after 3 seconds from passing file to binconverter)\n"
                        + "xml file should be in:\n"
                        + file2.getAbsolutePath() + "     Found: " + file2.exists());
                return null;
            }
        }
        if (timepassed > 6000 && !file2.canWrite()) {
            alertError("convert\nCan't write to the xml file after 6 seconds from passing the file to binconverter."
                    + file2.getAbsolutePath() + "     Can write: " + file2.canWrite());
            return null;
        }
    }

    return file2;
}

Answer 1

instead of having :

Runtime rt = Runtime.getRuntime();
.
.
.

try this instead:

 Process p = Runtime.getRuntime().exec("cmd.exe /c " + "\"\"" + this.currentPath + "\\GibbedsTools\\Gibbed.Avalanche.BinConvert.exe\" \"" + file.getAbsolutePath() + "\"\"");

then you can wait for it to finish by using:

p.waitFor();

once external program finishes it then releases the file. better solution would be using Processbuilder

You can also destroy the process by using

p.destroy();

of course try to avoid using it. unless program is pain to deal with.