VerboseRun.java

import java.io.File;
import java.lang.reflect.*;
import java.net.URL;
import java.net.URLClassLoader;

import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.generic.ClassGen;
import org.apache.bcel.util.ClassLoaderRepository;
import org.apache.bcel.util.ClassPath;

public class VerboseRun extends URLClassLoader {

	protected VerboseRun(URL[] urls, ClassLoader parent) {
		super(urls, parent);
	}

	@Override
	public Class loadClass(String name)
		throws ClassNotFoundException {
		Class klass = super.loadClass(name);
		return klass;
	}

	@Override
	protected Class findClass(String name)
		throws ClassNotFoundException {

		intercept(name);
		Class klass = super.findClass(name);
		return klass;
	}

	public void intercept(String name) {
		if(!name.equals("TestObject")) return;

		System.out.println("intercept loading of: " + name);
		ClassPath cp = new ClassPath();
		String classFilePath = null;

		try {
			classFilePath = cp.getClassFile(name, ".class").getPath();
			addSerializable(classFilePath);
		} catch(Exception e) {
			e.printStackTrace(System.out);
			return;
		}
	}

	public void addSerializable(String classFile) throws Exception {
		ClassParser cp = new ClassParser(classFile);
		JavaClass jc = cp.parse();
		System.out.println("Classname: " + jc.getClassName());

		String[] ifNames = jc.getInterfaceNames();
		for(String ifName: ifNames) {
			System.out.println("Interface before: " + ifName);
			if(ifName.equals("java.io.Serializable")) return;
		}

		ClassGen cg = new ClassGen(jc);
		cg.addInterface("java.io.Serializable");

		JavaClass jc2 = cg.getJavaClass();
		jc2.dump(classFile);
	}

	public static void main(String[] args) {
		if (args.length >= 1) {
			try {

				// load the target class to be run
				ClassLoader baseCl = ClassLoader.getSystemClassLoader();
				URL[] urls;
				if(baseCl instanceof URLClassLoader) {
					urls = ((URLClassLoader)baseCl).getURLs();
				} else {
					urls = new URL[] {
						new File(".").toURI().toURL()
					};
				}

				System.out.println("Loading from paths:");
				for (int i = 0; i < urls.length; i++) {
					System.out.println(" " + urls[i]);
				}

				VerboseRun loader = new VerboseRun(urls, baseCl.getParent());
				Class klass = loader.loadClass(args[0]);

				Class[] ptypes = new Class[] { args.getClass() };
				Method main = klass.getDeclaredMethod("main", ptypes);

				String[] pargs = new String[args.length-1];
				System.arraycopy(args, 1, pargs, 0, pargs.length);

				Thread.currentThread().setContextClassLoader(loader);

				main.invoke(null, new Object[] { pargs });

			} catch(Exception e) {
				e.printStackTrace();
			}

		} else {
			System.out.println
				("Usage: Run main-class args...");
		}
	}
}