Calculate the size of the directory using queue

SizeCalculationUsingQueue2.java

package sizecalculation;

import java.io.File;
import java.util.*;

public class SizeCalculationUsingQueue2 {
    private static Queue<File> queue = new LinkedList<>();
    static long size = 0;

    public static long getSize(File dir) {

        queue.addAll(Arrays.asList(dir.listFiles()));

        File file;
        while ((file = queue.poll()) != null) {
            if (file.isFile()) {
                size += file.length();
            } else {
                queue.addAll(Arrays.asList(file.listFiles()));
            }
        }

        return size;
    }

    public static void main(String[] args) {
        File dir = new File("D:\\java\\TaiLieu\\__MACOSX");

        System.out.println("Total size of directory = " + getSize(dir) + " bytes");
    }
}