import java.io.*;
import java.util.ArrayList;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class CustomClassLoader extends ClassLoader {
	
	private ArrayList<Class<?>> classes = new ArrayList<Class<?>>();
	
	public CustomClassLoader() {
		super(CustomClassLoader.class.getClassLoader());
	}
	
	@Override
	public Class<?> findClass(String name) {
		for (Class<?> cls : classes) {
			if (cls.getName().equals(name))
				return cls;
		}
		return null;
	}
	
	private void loadClasses(String zipPath) {
		try {
			ZipInputStream in = new ZipInputStream(new FileInputStream(zipPath));
			ZipEntry entry;
			while ((entry = in.getNextEntry()) != null) {
				if (!entry.isDirectory()) {
					byte[] buffer = new byte[(int) entry.getSize()];
					in.read(buffer);
					if (!entry.getName().endsWith(".class"))
						continue;
					String name = entry.getName().replace(".class", "").replace("/", ".");
					Class<?> cls = this.defineClass(name, buffer, 0, buffer.length);
					this.resolveClass(cls);
					classes.add(cls);
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		CustomClassLoader loader = new CustomClassLoader();
		loader.loadClasses("C:\\classes.zip);
	}

}