[JAVA] I want to recursively search the class list under the package

As a system engineer of SIer, I spend every day earning daily money, but recently I had the opportunity to create a design document (?) That says, "List the created Java classes by giving them package names." It's a reckless story that manual work is troublesome because of the number of Java classes created. Therefore, I decided to write a program that recursively searches for __packages and outputs a list of classes with package names. Below is a sample.


For example, if you have a project with the above package structure, the program that outputs the classes under "jp.co" with the package name should be as follows.

import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Enumeration;
import java.util.PriorityQueue;

public class Main {
    private static final String PACKAGE_SEPARATOR = ".";
    private static final String CLASS_SUFFIX = ".class";
    public static void main(String[] args) throws IOException, URISyntaxException {
        //Use the class loader to get the resources under the package.
        String rootPackageName = "jp.co".replace(PACKAGE_SEPARATOR, File.separator);
        ClassLoader classLoader = ClassLoader.getSystemClassLoader();
        Enumeration<URL> rootUrls = classLoader.getResources(rootPackageName);
        //Recursively search directories".class"If you find a file that ends with
        //After formatting the character string, store it in the list.
        PriorityQueue<String> classNames = new PriorityQueue();
        while (rootUrls.hasMoreElements()) {
            URL rootUrl = rootUrls.nextElement();
            Path rootPath = Paths.get(rootUrl.toURI());
            Files.walkFileTree(rootPath, new SimpleFileVisitor<Path>(){
                public FileVisitResult visitFile(Path path, BasicFileAttributes attrs) throws IOException {
                    String pathName = path.toString();
                    if (pathName.endsWith(CLASS_SUFFIX)) {
                        int beginIndex = pathName.lastIndexOf(rootPackageName);
                        int endIndex = pathName.lastIndexOf(CLASS_SUFFIX);
                        String className = pathName.substring(beginIndex, endIndex)
                                                   .replace(File.separator, PACKAGE_SEPARATOR);
                    return super.visitFile(path, attrs);
        //Output a list of found class names.
        for (String className : classNames) {

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