Java: Reflecting to Get All Classes in a Package, check and invoke method dynamically

It took me a little while to figure out that Java doesn't provide a way to reflect an entire package. In other words, there is no built-in way for me to dynamically retrieve a list of all the classes in a given package in Java through reflection. So I wrote my own method to do it.
Since it took a bit of googling and effort, I thought it would be nice to share the convenience method I wrote with the world. Enjoy:

Main.java under code.com.pritom package

package code.com.pritom;

import java.io.File;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;

public class Main {
    java.lang.reflect.Method method;

    public static void main(String[] args) throws Exception{
        Main main = new Main();
    }

    public Main() throws Exception{
        Class loadClass = getClassObjectByName("Load");
        System.out.println("Product Type Class: " + loadClass);
        System.out.println("Product Type Simple Name: " + loadClass.getSimpleName());
        System.out.println("Product Type Package Name: " + loadClass.getPackage().getName());
        System.out.println("Product Type Is Enum: " + loadClass.isEnum());

        try {
            method = loadClass.getMethod("println", String.class);
            System.out.println("Method Exists: println(String.class)");
            method.invoke(loadClass.newInstance(), "Pritom");
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }

        try {
            Class[] classes = new Class[2];
            classes[0] = String.class;
            classes[1] = Integer.class;
            method = loadClass.getMethod("println", classes);
            System.out.println("Method Exists: println(String.class, Integer.class)");
            method.invoke(loadClass.newInstance(), "Pritom", 26);
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    }

    private static HashMap allClassList = new HashMap();
    private static HashMap classObjectList = new HashMap();
    private static HashMap allClassObjectList = new HashMap();

    public static Class getClassObjectByName(String name) throws Exception {
        if(allClassObjectList.containsKey(name)) {
            return (Class) allClassObjectList.get(name);
        }
        String packageName = "code.com.pritom";
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        String path = packageName.replace('.', '/');
        Enumeration<URL> resources = classLoader.getResources(path);
        List<File> dirs = new ArrayList<File>();
        while (resources.hasMoreElements()) {
            URL resource = resources.nextElement();
            dirs.add(new File(resource.getFile()));
        }
        ArrayList<String> classes = new ArrayList<String>();
        for (File directory : dirs) {
            findClasses(directory, packageName);
        }
        if(allClassList.containsKey(name)) {
            Object object = getClassObjectByFullName(allClassList.get(name).toString()); /* Get the object */
            allClassObjectList.put(name, object); /* Storing for further use by class name only */
            return (Class) object; /* Return object */
        }
        throw new Exception("Invalid entity '" + name + "'");
    }

    private static void findClasses(File directory, String packageName) throws ClassNotFoundException {
        if (!directory.exists()) {
            return;
        }
        File[] files = directory.listFiles();
        for (File file : files) {
            if (file.isDirectory()) {
                findClasses(file, packageName + "." + file.getName());
            } else if (file.getName().endsWith(".class")) {
                allClassList.put(file.getName().substring(0, file.getName().length() - 6), packageName + "." + file.getName().substring(0, file.getName().length() - 6));
            }
        }
    }

    private static Object getClassObjectByFullName(String fullName) throws Exception {
        if (classObjectList.containsKey(fullName)) {
            return classObjectList.get(fullName);
        }
        try {
            ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
            Object object = Class.forName(fullName, true, classLoader);
            classObjectList.put(fullName, object); /* Storing by (package + class) name */
            return object;
        } catch (Exception ex) {
            throw new Exception(fullName + " does not appear to be a valid class.");
        }
    }
}

And Load.java under code.com.pritom package

package code.com.pritom;

public class Load {
    public void println(String text) {
        System.out.println("\tName: " + text);
    }
    public void println(String text, Integer age) {
        System.out.println("\tName: " + text +", Age: " + age);
    }
}

---

And output will be as follows:

Product Type Class: class code.com.pritom.Load
Product Type Simple Name: Load
Product Type Package Name: code.com.pritom
Product Type Is Enum: false
Method Exists: println(String.class)
	Name: Pritom
Method Exists: println(String.class, Integer.class)
	Name: Pritom, Age: 26