- Given a base & concrete class in java.
- Base class is not Serializable
- Concrete class implements Serializable interface and extending its base class
- Base class must have default or no arg constructor.
- We have discussed
- Impact of Inheritance on serialization in java, when base class is serializable.
Impact of serialization on inheritance in java
1.) What happens, when concrete class is serialized?
- Date members of concrete class will get serialized
- Date members of base class will not get serialized
2.) What happens, when concrete class is deserialized?
- Data members of concrete class gets deserialized
- Data members of base class get default value
Fig 1: Employee implements Serializable
Code: Serialization when concrete class is serializable
1.) Person (Base) class (is not serializable)
- Person class does not implements Serializable interface.
- Data members of Person class will not be serialized.
package org.learn;
public class Person {
public String firstName;
public int age;
public String contact;
public Person(String firstName,int age, String contact) {
this.firstName = firstName;
this.age = age;
this.contact = contact;
}
public Person() {
}
public String toString() {
return "[" + firstName +
" " + age + " " +contact +"]";
}
}
2.) Employee (Concrete) class implements Serializable interface
- Employee class implements Serializable marker interface
- Employee class extends Person class.
- When we will serialize the Employee object
- Data member pertaining to employee object will gets serialized
- Data members of person class will not get serialized.
- When we deserialize the employee object
- Employee data members will gets deserialized.
- Person data members will get default values (will not get serialized).
package org.learn;
import java.io.Serializable;
public class Employee extends Person implements Serializable {
private static final long serialVersionUID = 1L;
public String department;
public int employCode = 1010;
public int salary;
public Employee(String department,int salary, int employCode,
String firstName,int age, String contact) {
super(firstName,age, contact);
this.department = department;
this.salary = salary;
this.employCode = employCode;
}
public String toString() {
return super.toString() + "[" + department + " " + employCode +
" " + salary + "]";
}
}
3.) SerializeDeserialize class
- SerializeDeserialize class contains main function.
- SerializeDeserialize class will serialize and deserialize the Employee object.
package org.learn;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class SerializeDeserialize {
public static void serialize() throws IOException {
Employee employee = new Employee("IT", 25, 9999, "Mike", 34, "001894536");
//Set static variable
FileOutputStream output = new FileOutputStream(new File("savePerson.txt"));
ObjectOutputStream outputStream = new ObjectOutputStream(output);
outputStream.writeObject(employee);
output.close();
outputStream.close();
System.out.println("Serialized the employee object : "+employee);
}
public static void deSerialize() throws IOException, ClassNotFoundException {
FileInputStream inputStream = new FileInputStream(new File("savePerson.txt"));
ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
Employee employee = (Employee) objectInputStream.readObject();
System.out.println("Deserialize the employee object :"+ employee);
objectInputStream.close();
inputStream.close();
}
public static void main(String[] args) throws IOException, ClassNotFoundException {
serialize();
deSerialize();
}
}
Output: Serialization in java, drive class is serializable
Serialized the employee object : [Mike 34 001894536][IT 9999 25]
Deserialize the employee object :[null 0 null][IT 9999 25]
