Immutable Class Constructor with Defensive Copies

Immutable class Constructor have Defensive Copies

To make the class immutable, the constructor will create a new object from the value and then assign it to a class member, so that the object reference cannot be modified later.

package org.wesome.dsalgo;

import java.util.Date;
import java.util.Objects;

public class Apple {
    String name;
    float price;
    Date date;

    public Apple() {
    }

    public Apple(String name, float price, Date date) {
        this.name = name;
        this.price = price;
        this.date = new Date(date.getYear(), date.getMonth(), date.getDate(), date.getHours(), date.getMinutes(), date.getSeconds());
    }

    public String getName() {
        return name;
    }

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

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Apple apple = (Apple) o;
        return Float.compare(apple.price, price) == 0 && Objects.equals(name, apple.name) && Objects.equals(date, apple.date);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, price, date);
    }

    @Override
    public String toString() {
        return "Apple{" +
                "name='" + name + '\'' +
                ", price=" + price +
                ", date=" + date +
                '}';
    }
}

package org.wesome.dsalgo;

import org.junit.jupiter.api.Test;

import java.util.Date;

public class AppleTest {
    @Test
    public void finalFieldTest() {
        Date date = new Date();
        Apple apple = new Apple("Mcintosh", 1.1f, date);
        System.out.println(apple);
        date.setYear(100);
        System.out.println(apple);
    }
}

plugins {
    id 'java'
    id "io.freefair.lombok" version "6.2.0"
}

group = 'org.wesome'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = JavaVersion.VERSION_1_8

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter:5.6.2'
}

test {
    useJUnitPlatform()
}