Java by API/java.io/Externalizable

implements Externalizable

   <source lang="java">

import java.io.Externalizable; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInput; import java.io.ObjectInputStream; import java.io.ObjectOutput; import java.io.ObjectOutputStream; class A implements Externalizable {

 public A() {
   System.out.println("A Constructor");
 }
 public void writeExternal(ObjectOutput out) throws IOException {
   System.out.println("A.writeExternal");
 }
 public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
   System.out.println("A.readExternal");
 }

} class B implements Externalizable {

 B() {
   System.out.println("B Constructor");
 }
 public void writeExternal(ObjectOutput out) throws IOException {
   System.out.println("B.writeExternal");
 }
 public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
   System.out.println("B.readExternal");
 }

} public class Main {

 public static void main(String[] args) throws IOException, ClassNotFoundException {
   A b1 = new A();
   B b2 = new B();
   ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream("File.out"));
   o.writeObject(b1);
   o.writeObject(b2);
   o.close();
   ObjectInputStream in = new ObjectInputStream(new FileInputStream("File.out"));
   b1 = (A) in.readObject();
 }

}

 </source>