Sorting output from largest to smallest?

Question

What is the easiest way to sort the output of this code by size from largest to smallest? It's a small code which check total size of path passed from command line. It shows the file of the directory specify in a path and a total size of folders inside the directory, which I want to sort by size from largest to smallest?

import java.io.File;

public class ShowSize{

public static void main(String[] args) {
    ShowSize ss = new ShowSize();
    ss.showFileSizes(new File(args[0]));
}
// this method get call from main first
public static void showFileSizes(File dir) {
    // assign path from command line to an array using listFiles() method
    File[] files = dir.listFiles();
    // create a arrays of long to calculate a size of subdirectories
    long [] fileSizes = new long[files.length];                 
    for (int i = 0; i < files.length; i++) {
        fileSizes[i] = calculateFileSize(files[i]);
        //create a boolean variable to check if file is a type of FILE or DIR
        boolean isDirectory = files[i].isDirectory();
        //show the results  
        System.out.println(((isDirectory) ? "DIR" : "FILE") + " - "+ files[i].getAbsolutePath() + " "+ showFileSize(fileSizes[i]));
    }
}
// this method get call from showFileSize() every time the new path get loaded.
public static long calculateFileSize(File file) {
    long fileSize = 0L;
    if (file.isDirectory()) {
        File[] children = file.listFiles();                 
        for (File child : children) {
            fileSize += calculateFileSize(child);
        }
    } else {
        fileSize = file.length();
    }
    return fileSize;
}
// get the size of file in nice  and easy to read format
public static String showFileSize(long size) {
    String unit = "bytes";
    if (size > 1024) {
        size = size / 1024;
        unit = "kb";
    }
    if (size > 1024) {
        size = size / 1024;
        unit = "mb";
    }
    if (size > 1024) {
        size = size / 1024;
        unit = "gb";
    }
    return "(" + size + ")" + unit;
}   
}

Answer 1

What is the easiest way to sort the output of this code by size from largest to smallest

If you want to sort by size try the following code:

Arrays.sort(files, new Comparator<File>() {
    public int compare(File file1, File file2) {
        return Long.compare(file2.length(), file1.length()); // or apply your logic
    }
});

Where files is an array of File

[UPDATE] length() returns long value... updated (based on comment by lassana)