New to Java

Basically im writing a script system which uses class files as scripts and each class file overrides the Script superclass.

However, when i try and cast it when loading it's giving me the error;

"Cannot be cast to Script".

Here are my classes;

ClassLoaderSub.java

import java.security.AllPermission;
import java.security.CodeSource;
import java.security.Permissions;
import java.security.ProtectionDomain;
import java.security.cert.Certificate;
import java.util.Hashtable;

public class ClassLoaderSub extends ClassLoader {

    public Hashtable loadedClasses = new Hashtable();
    public ProtectionDomain protectionDomain;
    public ScriptUnpacker scriptUnpacker;

    public ClassLoaderSub() {
        CodeSource codeSource = new CodeSource(null, (Certificate[]) null);
        Permissions permissions = new Permissions();
        permissions.add(new AllPermission());
        protectionDomain = new ProtectionDomain(codeSource, permissions);
    }

    public synchronized Class loadClass(String className, boolean resolve) throws ClassNotFoundException {
	System.out.println(className);
        Class rsClass = (Class) loadedClasses.get(className);
        if (rsClass != null) {
            return rsClass;
        }
        if (scriptUnpacker != null) {
            byte[] classBytes = scriptUnpacker.getClassBytes(className);
            if (classBytes != null) {
                rsClass = defineClass(className, classBytes, 0, classBytes.length, protectionDomain);
                if (resolve) {
                    resolveClass(rsClass);
                }
                loadedClasses.put(className, rsClass);
                return rsClass;
            }
        }
        return super.findSystemClass(className);
    }
}

Script.java

public abstract class Script {

	public abstract void method1();

	public abstract void method2();

}

ScriptUnpacker.java

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

public class ScriptUnpacker {

    public Hashtable classBytes = new Hashtable();

    public ScriptUnpacker()
    {
        unpack();
    }

    public void unpack()
    {
        try {
            File[] scripts = new File("./scripts").listFiles();
            for (File f : scripts)
            {
                if(!f.getName().endsWith(".class"))
                    continue;
                String entryName = f.getName().substring(0, f.getName().length() - 6);
                byte[] buffer = new byte[(int) f.length()];
                DataInputStream reader = new DataInputStream(new FileInputStream(f));
                reader.readFully(buffer);
                reader.close();
                classBytes.put(entryName, buffer);
            }
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public byte[] getClassBytes(String className)
    {
        return (byte[]) classBytes.remove(className);
    }

}

One.java - Test script

public class One extends Script {

    public One()
    {
        System.out.println("Loaded one.");
    }

    @Override
    public void method1()
    {
        System.out.println("method 1");
    }

    @Override
    public void method2()
    {
        System.out.println("method 2");
    }

}

And finally my main class;

Main.java

public class Main {

	public static void main(String[] args)
	{
		try {
			ClassLoaderSub cls = new ClassLoaderSub();
			cls.scriptUnpacker = new ScriptUnpacker();
			Class script = cls.loadClass("One");
			Script sc = (Script) script.newInstance();
		} catch(Exception e) {
			e.printStackTrace();
		}
	}

}

Thanks for any help.