Serialization and de-serialization,

package demo06;

import java.io.Serializable;

public class Pserson implements Serializable {
    private static final long serialVersionUID = 1L;
    private  String  name;
    private int age;

    @Override
    public String toString() {
        return "Pserson{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public Pserson(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public Pserson() {
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

Add this

serialVersionUID = 1L; Control can 
change causes a change in each category class Serializable ID, when given deserialization

serialVersionUID = 1L; is this class has been the same ID