It is very tricky to prevent serialization of child class if the base class is intended to implement the Serializable interface. However, we cannot do it directly, but the serialization can be avoided by implementing the writeObject() or readObject() methods in the subclass and throw NotSerializableException from these methods. Consider the following example.
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.NotSerializableException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
class Person implements Serializable
{
String name = " ";
public Person(String name)
{
this.name = name;
}
}
class Employee extends Person
{
float salary;
public Employee(String name, float salary)
{
super(name);
this.salary = salary;
}
private void writeObject(ObjectOutputStream out) throws IOException
{
throw new NotSerializableException();
}
private void readObject(ObjectInputStream in) throws IOException
{
throw new NotSerializableException();
}
}
public class Test
{
public static void main(String[] args)
throws Exception
{
Employee emp = new Employee("Sharma", 10000);
System.out.println("name = " + emp.name);
System.out.println("salary = " + emp.salary);
FileOutputStream fos = new FileOutputStream("abc.ser");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(emp);
oos.close();
fos.close();
System.out.println("Object has been serialized");
FileInputStream f = new FileInputStream("ab.txt");
ObjectInputStream o = new ObjectInputStream(f);
Employee emp1 = (Employee)o.readObject();
o.close();
f.close();
System.out.println("Object has been deserialized");
System.out.println("name = " + emp1.name);
System.out.println("salary = " + emp1.salary);
}
}
