Run all test classes that are extending specific class

AllTests.java

package com.abc.common;

import static java.lang.Class.forName;
import static java.lang.Thread.currentThread;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import junit.framework.JUnit4TestAdapter;
import junit.framework.TestCase;
import junit.framework.TestSuite;

public class AllTests extends TestCase {
    private static final Class<?> SUPER_CLASS = TestBase.class;
    private static final String PACKAGE = "com.abc";

    public static TestSuite suite() throws ClassNotFoundException, IOException {
        TestSuite suite = new TestSuite();
        for (Class<?> claz : getClasses(PACKAGE, SUPER_CLASS)) {
            suite.addTest(new JUnit4TestAdapter(claz));
            System.out.println(claz.getName());
        }
        return suite;
    }

    private static ArrayList<Class<?>> getClasses(String packageName, Class<?> superClass)
            throws ClassNotFoundException, IOException {
        ClassLoader classLoader = currentThread().getContextClassLoader();
        assert classLoader != null;
        Enumeration<URL> resources = classLoader.getResources(packageName.replace('.', '/'));
        List<File> dirs = new ArrayList<>();
        while (resources.hasMoreElements()) {
            dirs.add(new File(resources.nextElement().getFile()));
        }
        ArrayList<Class<?>> classes = new ArrayList<>();
        for (File directory : dirs) {
            classes.addAll(findClasses(directory, packageName, superClass));
        }
        return classes;
    }

    private static List<Class<?>> findClasses(File directory, String packageName, Class<?> superClass)
            throws ClassNotFoundException {
        List<Class<?>> classes = new ArrayList<>();
        if (directory.exists()) {
            for (File file : directory.listFiles()) {
                String fileName = file.getName();
                if (file.isDirectory()) {
                    assert !fileName.contains(".");
                    classes.addAll(findClasses(file, packageName + "." + fileName, superClass));
                } else if (fileName.endsWith("Test.class")) {
                    Class<?> testClass = forName(packageName + '.' + fileName.substring(0, fileName.length() - 6));
                    if (testClass.getSuperclass().equals(superClass)) {
                        classes.add((Class<?>) testClass);
                    }
                }
            }
        }
        return classes;
    }
}