}

        @Override
        public void writeExternal(final ObjectOutput s) throws IOException {
            s.writeInt(hashCode);
            s.writeObject(key);
            s.writeObject(value);
            s.writeObject(next);
        }

        @SuppressWarnings("unchecked")
        @Override
        public void readExternal(final ObjectInput s) throws IOException, ClassNotFoundException {

        try {
            final ByteArrayOutputStream baos = new ByteArrayOutputStream(BYTE_ARRAY_SIZE);
            final ObjectOutputStream oos = new ObjectOutputStream(baos);
            try {
                oos.writeObject(obj);
            } finally {
                oos.close();
            }
            return baos.toByteArray();
        } catch (final IOException ex) {
            throw new IORuntimeException(ex);
        }

    }

    @Override
    public void writeExternal(final ObjectOutput s) throws IOException {
        s.writeInt(size);
        for (Entry e = header.next; e != header; e = e.next) {
            s.writeObject(e.element);
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public void readExternal(final ObjectInput s) throws IOException, ClassNotFoundException {