deep cloning

Here is a small utility to really clone an object by writing it first to outputstream and back.

    public static Object deepClone(Object src) throws IOException,ClassNotFoundException{
            ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
            ObjectOutputStream oos = new ObjectOutputStream(baos);
            oos.writeObject(src);
            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
            ClassLoaderObjectInputStream ois = new  ClassLoaderObjectInputStream(src.getClass().getClassLoader(),bais);
            Object deepCopy = ois.readObject();
            return  deepCopy;
    }

The class ClassLoaderObjectInputInputStream is needed to resolve the class if it is not in the same jar as the utility method deepClone

import java.io.ObjectInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectStreamClass;
import java.io.StreamCorruptedException;

/**
 * A special ObjectInputStream that loads a class based on a specified
 * ClassLoader rather than the system default.
 *
 * This is useful in dynamic container environments.
 *
 * @author Paul Hammant
 * @version $Id: ClassLoaderObjectInputStream.java 437567 2006-08-28 06:39:07Z bayard $
 * @since Commons IO 1.1
 */
public class ClassLoaderObjectInputStream extends ObjectInputStream {
    /** The class loader to use. */
    private ClassLoader classLoader;

    /**
     * Constructs a new ClassLoaderObjectInputStream.
     *
     * @param classLoader  the ClassLoader from which classes should be loaded
     * @param inputStream  the InputStream to work on
     * @throws IOException in case of an I/O error
     * @throws StreamCorruptedException if the stream is corrupted
     */
    public ClassLoaderObjectInputStream(
            ClassLoader classLoader, InputStream inputStream)
            throws IOException, StreamCorruptedException {
        super(inputStream);
        this.classLoader = classLoader;
    }

    /**
     * Resolve a class specified by the descriptor using the
     * specified ClassLoader or the super ClassLoader.
     *
     * @param objectStreamClass  descriptor of the class
     * @return the Class object described by the ObjectStreamClass
     * @throws IOException in case of an I/O error
     * @throws ClassNotFoundException if the Class cannot be found
     */
    protected Class resolveClass(ObjectStreamClass objectStreamClass)
            throws IOException, ClassNotFoundException {
       
        Class clazz = Class.forName(objectStreamClass.getName(), false, classLoader);

        if (clazz != null) {
            // the classloader knows of the class
            return clazz;
        } else {
            // classloader knows not of class, let the super classloader do it
            return super.resolveClass(objectStreamClass);
        }
    }
}