Example of Serializing some classes.

Serialization.java

import javax.imageio.IIOException;
import javax.swing.*;
import java.io.*;

public class HyperSkill {

    public static void main(String[] args) {
        Person simon = new Person("simon", 21, new Address("stillwater", "uk"));
        String fileName = "C:\\users\\si_au\\desktop\\simon.data";
        try {
            SerializationUtils.serialize(simon, fileName);
            Person deserializedSimon = (Person) SerializationUtils.deserialize(fileName);
            System.out.println(deserializedSimon.getName());
            System.out.println(deserializedSimon.getAddress().getStreet());
        } catch (IOException | ClassNotFoundException e) {
            System.out.println("some problem");
        }
    }

}

class Person implements Serializable {

    private static final long serialVersionUID = 1L;

    String name;
    int age;
    Address address;

    public Person(String name, int age, Address address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public void setName(String name) {
        this.name = name;
    }
}

class Address implements Serializable {

    private static final long serialVersionUID = 564320375408842791L;

    String street;
    String country;

    public Address(String street, String country) {
        this.country = country;
        this.street = street;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }
}

class SerializationUtils {
    /**
     * Serialize the given object to the file
     */
    public static void serialize(Object obj, String fileName) throws IOException {
        FileOutputStream fos = new FileOutputStream(fileName);
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(obj);
        oos.close();
    }

    /**
     * Deserialize to an object from the file
     */
    public static Object deserialize(String fileName) throws IOException, ClassNotFoundException {
        FileInputStream fis = new FileInputStream(fileName);
        BufferedInputStream bis = new BufferedInputStream(fis);
        ObjectInputStream ois = new ObjectInputStream(bis);
        Object obj = ois.readObject();
        ois.close();
        return obj;
    }
}