import java.io.*;

class Data implements Serializable {
	int n;
	Data next;

	public Data(int n) {
		this.n = n;
	}
}

public class Serial {
	public static void main(String[] args) throws ClassNotFoundException, IOException {
		Data d1 = new Data(1);
		d1.next = new Data(2);
		d1.next.next = d1;
		
		ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("d.out"));
		out.writeObject(d1);
		out.close();
		
		ObjectInputStream in = new ObjectInputStream(new FileInputStream("d.out"));
		Data d2 = (Data)in.readObject();
		in.close();
		
		System.out.println(d2.n + ", next " + d2.next.n + ", and back " + d2.next.next.n);
	}
}