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();
}
}