// serialization/MyWorld.java // (c)2017 MindView LLC: see Copyright.txt // We make no guarantees that this code is fit for any purpose. // Visit http://OnJava8.com for more book information. import java.io.*; import java.util.*; class House implements Serializable {} class Animal implements Serializable { private String name; private House preferredHouse; Animal(String nm, House h) { name = nm; preferredHouse = h; } @Override public String toString() { return name + "[" + super.toString() + "], " + preferredHouse + "\n"; } } public class MyWorld { public static void main(String[] args) throws IOException, ClassNotFoundException { House house = new House(); List animals = new ArrayList<>(); animals.add(new Animal("Bosco the dog", house)); animals.add(new Animal("Ralph the hamster", house)); animals.add(new Animal("Molly the cat", house)); System.out.println("animals: " + animals); try( ByteArrayOutputStream buf1 = new ByteArrayOutputStream(); ObjectOutputStream o1 = new ObjectOutputStream(buf1) ) { o1.writeObject(animals); o1.writeObject(animals); // Write a 2nd set // Write to a different stream: try( ByteArrayOutputStream buf2 = new ByteArrayOutputStream(); ObjectOutputStream o2 = new ObjectOutputStream(buf2) ) { o2.writeObject(animals); // Now get them back: try( ObjectInputStream in1 = new ObjectInputStream( new ByteArrayInputStream( buf1.toByteArray())); ObjectInputStream in2 = new ObjectInputStream( new ByteArrayInputStream( buf2.toByteArray())) ) { List animals1 = (List)in1.readObject(), animals2 = (List)in1.readObject(), animals3 = (List)in2.readObject(); System.out.println("animals1: " + animals1); System.out.println("animals2: " + animals2); System.out.println("animals3: " + animals3); } } } } } /* Output: animals: [Bosco the dog[Animal@1db9742], House@106d69c , Ralph the hamster[Animal@52e922], House@106d69c , Molly the cat[Animal@25154f], House@106d69c ] animals1: [Bosco the dog[Animal@1a4f24f], House@19a45b3 , Ralph the hamster[Animal@99a589], House@19a45b3 , Molly the cat[Animal@372a00], House@19a45b3 ] animals2: [Bosco the dog[Animal@1a4f24f], House@19a45b3 , Ralph the hamster[Animal@99a589], House@19a45b3 , Molly the cat[Animal@372a00], House@19a45b3 ] animals3: [Bosco the dog[Animal@dd8dc3], House@103e736 , Ralph the hamster[Animal@8db2f2], House@103e736 , Molly the cat[Animal@18bf509], House@103e736 ] */