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Java • Multiple Inheritance Using Interface



Amongst the many facets of object-oriented programming, the concept of inheritance is fundamental. Multiple inheritance, a feature where a class can inherit from more than one superclass, can be particularly powerful but also complex. Java, however, does not support multiple inheritance directly in the way languages like C++ do. Instead, it offers a robust alternative through interfaces. This article will delve into the concept of multiple inheritance in Java using interfaces, providing practical examples and best practices.

Multiple Inheritance Through Class Inheritance

The history behind the absence of multiple inheritance in Java through traditional means, like class inheritance, is rooted in the language’s design philosophy and the complexities associated with multiple inheritance in other programming languages.

  1. Simplification of Language Design: Java was designed with the goal of being simple and secure. The creators of Java, led by James Gosling at Sun Microsystems, wanted to build a language that was easier to understand and more robust than its predecessors like C++. One of the complexities in C++ that they aimed to avoid was the ambiguity and complication arising from multiple inheritance.

  2. The Diamond Problem: A significant issue with multiple inheritance is the “diamond problem,” a scenario where a class inherits from two classes that have a common base class. This creates ambiguity in the path through which the base class is accessed. For instance, if class D inherits from both class B and class C, and these two classes inherit from a common class A, it becomes unclear which path to class A should be taken. This can lead to issues with data duplication and ambiguity in method calls.

  3. Increased Complexity and Ambiguity: Multiple inheritance can make the code more complex and difficult to understand. It increases the risk of naming collisions and ambiguities in the hierarchy, making the programming model less clear and more prone to errors.

  4. Design Alternative - Interfaces: To address these challenges, Java designers opted for a single inheritance model supplemented by interfaces. Interfaces in Java allow a class to inherit multiple sets of behavior without the pitfalls of multiple inheritance. This design promotes code reusability and polymorphism while keeping the language simpler and more maintainable.

  5. Focus on Composition over Inheritance: Java’s design encourages composition over inheritance. Composition involves creating objects that contain instances of other classes that implement the desired functionality. This approach is more flexible and leads to less tightly coupled code compared to classical inheritance, especially multiple inheritance.

  6. Evolution of Interface Concept: Over time, Java has evolved the concept of interfaces. With the introduction of default methods in Java 8, interfaces in Java can now contain method implementations. This development has further reduced the need for multiple inheritance by allowing interfaces to provide “mixin-like” functionality, which was one of the use cases for multiple inheritance.

In summary, the decision to exclude traditional multiple inheritance from Java was a deliberate design choice aimed at simplifying the language, avoiding the complexities and ambiguities associated with multiple inheritance seen in languages like C++, and promoting clearer and more maintainable code structures. Instead, Java uses interfaces to enable a form of multiple inheritance that aligns with its design principles.

Understanding Basic Interfaces

An interface in Java is an abstract type that is used to specify a behavior that classes must implement. Interfaces are about capabilities - what an object can do - rather than about what it is. For instance, any object that can fly might implement a FlyingVehicle interface, which could declare methods like fly() and land(). This does not describe what the object is (like a plane or a bird), but rather what it can do.

To implement an interface in Java, a class must provide concrete implementations of all the methods declared in the interface. For example, a class Airplane might implement the FlyingVehicle interface by providing specific code for how an Airplane flies and lands.

Here’s an example that illustrates the concept of implementing an interface in Java using a FlyingVehicle interface and an Airplane class:

Figure 1. FlyingVehicle Interface and an Airplane Class Diagram

Also available in: SVG | PlantText
// Define a FlyingVehicle interface
interface FlyingVehicle {
    void fly();  // Declare a method for flying
    void land(); // Declare a method for landing

// Implement the FlyingVehicle interface with the Airplane class
class Airplane implements FlyingVehicle {
    public void fly() {
        System.out.println("The airplane is taking off and flying.");
        // Implement the specific flying behavior for an airplane

    public void land() {
        System.out.println("The airplane is landing.");
        // Implement the specific landing behavior for an airplane

public class Main {
    public static void main(String[] args) {
        // Create an instance of the Airplane class
        Airplane myAirplane = new Airplane();

        // Call the fly() and land() methods on the airplane

In this example:

  1. We define a FlyingVehicle interface with two abstract methods: fly() and land(). These methods declare the behavior that any flying vehicle should implement.

  2. The Airplane class implements the FlyingVehicle interface. To do so, it provides concrete implementations of the fly() and land() methods. These implementations specify how an airplane should fly and land.

  3. In the main method, we create an instance of the Airplane class (myAirplane) and then call the fly() and land() methods on it. This demonstrates that the Airplane class implements the FlyingVehicle interface and provides the expected behavior for flying and landing.

This example illustrates how interfaces in Java define a contract of behavior that implementing classes must adhere to. The Airplane class, in this case, implements the FlyingVehicle interface by providing specific implementations for the required methods.

Interface with Default or Static Methods

Java 8 introduced default and static methods in interfaces, adding more flexibility. A default method is a non-abstract method, which provides a default implementation. This means that classes implementing the interface can either use this default implementation or provide their own version.

Static methods in interfaces help in providing utility methods relevant to the interface. They are not inherited by the implementing classes, thus maintaining the interface’s purity while offering practical functionality.

Static vs Default Methods in Java Interfaces

Static vs default methods in Java Interfaces serve different purposes.

Static Methods


Figure 2. Static Methods in Java Interfaces

Also available in: SVG | PlantText
interface MyInterface {
    static void staticMethod() {
        System.out.println("This is a static method in the interface.");

class MyClass implements MyInterface {
    // You can't override a static method; you can only hide it
    static void staticMethod() {
        System.out.println("This is a static method in the class.");

Default Methods

Basic Example:

Figure 3. Default Methods in Interface

Also available in: SVG | PlantText
interface MyInterface {
    default void defaultMethod() {
        System.out.println("This is a default method in the interface.");

class MyClass implements MyInterface {
    // You can choose to override the default method
    public void defaultMethod() {
        System.out.println("This is an overridden default method in the class.");

Ambiguity Example:

When a class inherits multiple interfaces that have methods with the same name, the inheriting class needs to explicitly resolve the ambiguity by providing its own implementation of the conflicting method. Here’s an example to illustrate this:

Figure 4. Interface Implementations With Ambiguity

Also available in: SVG | PlantText
// First interface with a default method named 'doSomething'
interface FirstInterface {
    default void doSomething() {
        System.out.println("Default implementation from FirstInterface");

// Second interface with a default method named 'doSomething'
interface SecondInterface {
    default void doSomething() {
        System.out.println("Default implementation from SecondInterface");

// A class that implements both interfaces and must resolve the ambiguity
class MyClass implements FirstInterface, SecondInterface {
    public void doSomething() {
        // Explicitly choosing to override the method
        System.out.println("Custom implementation in MyClass");

        // Optionally calling default implementation from one of the interfaces
        // SecondInterface.super.doSomething(); // Uncomment to use SecondInterface's implementation

public class Main {
    public static void main(String[] args) {
        MyClass myClass = new MyClass();
        myClass.doSomething(); // First calls MyClass's implementation, then FirstInterface's

In this example, we have two interfaces, FirstInterface and SecondInterface, both of which declare a method named doSomething. The MyClass class implements both interfaces, so it must provide its own implementation of the doSomething method to resolve the ambiguity.

In the MyClass implementation, we have overridden the doSomething method, and it will use this implementation when we call myClass.doSomething(). This allows the class to provide a specific behavior for the doSomething method, resolving the ambiguity caused by the method with the same name in both interfaces.

In summary, static methods in interfaces are associated with the interface itself, while default methods provide a default implementation that can be inherited by implementing classes. Static methods are not inherited, while default methods can be inherited and optionally overridden by implementing classes.

Multiple Inheritance-like Structure Through Interfaces

Is multiple inheritance possible in Java using interfaces? Absolutely. Interfaces allow Java to support multiple inheritance-like behavior. This is because a class in Java can implement multiple interfaces, thereby inheriting the abstract methods of multiple interfaces.

Take, for instance, a class FlyingCar that needs to function both as a Vehicle and as a FlyingVehicle. In Java, FlyingCar can implement both these interfaces, thereby inheriting their capabilities. It’s a way to have the best of both worlds, the functionalities of a regular vehicle and a flying vehicle, without the complexities and ambiguities often associated with multiple inheritance.

Practical Example: Vehicle and FlyingVehicle

How to use an interface for multiple classes in Java? Let’s illustrate this with our Vehicle and FlyingVehicle example. A basic Vehicle interface might declare methods like drive() and stop(). The FlyingVehicle interface, as already mentioned, would have methods like fly() and land(). A class like FlyingCar implementing both these interfaces would provide its own definitions for all these methods, thus exhibiting behaviors of both a regular vehicle and a flying vehicle.

Here’s an example to illustrate how a class in Java can implement multiple interfaces with default methods, specifically focusing on a FlyingCar class that implements both Vehicle and FlyingVehicle interfaces, each having a default method named stop().

In this scenario, the FlyingCar class’s stop() method will decide which interface’s stop() method to call based on whether the car is flying. This requires an additional method, isFlying(), to determine the car’s current state. Here’s how the implementation would look:


Figure 5. Multiple Inheritance with Ambiguity

Also available in: SVG | PlantText
// Interface for regular vehicles
interface Vehicle {
    void drive();

    // Default method 'stop'
    default void stop() {
        System.out.println("Vehicle stopped.");

// Interface for flying vehicles
interface FlyingVehicle {
    void fly();
    void land();

    // Default method 'stop'
    default void stop() {
        System.out.println("FlyingVehicle stopped.");

// Class that implements both interfaces
class FlyingCar implements Vehicle, FlyingVehicle {
    private boolean flying;

    public void drive() {
        System.out.println("FlyingCar is driving.");
        flying = false;

    public void fly() {
        System.out.println("FlyingCar is flying.");
        flying = true;

    public void land() {
        System.out.println("FlyingCar is landing.");
        flying = false;

    // Method to check if the car is currently flying
    private boolean isFlying() {
        return flying;

    public void stop() {
        // Decide which stop method to call based on flying state
        if (isFlying()) {
            FlyingVehicle.super.stop(); // Calls the stop method of FlyingVehicle interface
        } else {
            Vehicle.super.stop(); // Calls the stop method of Vehicle interface

public class Main {
    public static void main(String[] args) {
        FlyingCar myFlyingCar = new FlyingCar();
        myFlyingCar.stop(); // Output will depend on whether the car is flying or driving
        myFlyingCar.stop(); // Output will depend on the car's state

In this implementation, the FlyingCar class has a private field flying to keep track of whether it is flying. The isFlying() method checks this state. When stop() is called, it determines the appropriate action based on whether the FlyingCar is in flight. If it is flying, it calls the stop method from the FlyingVehicle interface; otherwise, it calls the stop method from the Vehicle interface. This approach elegantly handles the dynamic nature of a FlyingCar, providing context-specific behavior.

Proper Use of Multiple Inheritance Using Interface

What is the proper use of multiple inheritance using interface in Java? The key is to use interfaces for defining capabilities or behaviors and then implement those interfaces in classes that require those behaviors.

It’s crucial to design your interfaces thoughtfully, keeping them focused and not too broad. Overusing interfaces or making them too granular can lead to a confusing and hard-to-maintain codebase.

Example Usage of Interface Default Methods in Tests

Here’s an example of implementing two interfaces, JsonAssertions and RestAssertions, which have default methods, and a unit test that uses these interfaces to assert JSON content and RESTful responses:

First, let’s define the interfaces JsonAssertions and RestAssertions:

import org.junit.jupiter.api.Assertions;

// Interface for JSON assertions
interface JsonAssertions {
    default void assertJsonEquals(String expectedJson, String actualJson) {
        Assertions.assertEquals(expectedJson, actualJson, "JSON content does not match");

// Interface for REST assertions
interface RestAssertions {
    default void assertStatusCode(int expectedStatusCode, int actualStatusCode) {
        Assertions.assertEquals(expectedStatusCode, actualStatusCode, "HTTP Status code does not match");

Now, let’s create a test class that implements these interfaces and uses their default methods to perform assertions:

import org.junit.jupiter.api.Test;

class MyRestTest implements JsonAssertions, RestAssertions {
    // Simulated REST API response
    String jsonResponse = "{\"name\":\"John\",\"age\":30}";

    void testJsonAssertion() {
        String expectedJson = "{\"name\":\"John\",\"age\":30}";

        // Use the assertJsonEquals method from JsonAssertions
        assertJsonEquals(expectedJson, jsonResponse);

    void testRestAssertion() {
        int expectedStatusCode = 200;
        int actualStatusCode = 200; // Simulated response status code

        // Use the assertStatusCode method from RestAssertions
        assertStatusCode(expectedStatusCode, actualStatusCode);

In this example, the use of default methods in Java interfaces is appropriate and serves a specific purpose. Let’s discuss the appropriateness of this use case in more detail:

The example demonstrated two interfaces, JsonAssertions and RestAssertions, each defining a default method for performing specific types of assertions:

  1. JsonAssertions interface includes the assertJsonEquals default method for comparing JSON content.
  2. RestAssertions interface includes the assertStatusCode default method for asserting HTTP status codes.

In this example, the Test class is no longer implementing an interface but inheriting the operations of an interface through the use of default methods. Here’s why this use of default methods is proper:

  1. Interface Evolution and Backward Compatibility: Default methods in interfaces are designed for evolving interfaces without breaking existing implementations. In this case, if new assertion methods need to be added to these interfaces in the future, existing test classes that implement these interfaces won’t be forced to implement the new methods immediately. This is beneficial for maintaining backward compatibility and allowing for easy extension of the assertion capabilities.

  2. Code Organization and Reusability: Using default methods to encapsulate common assertion logic (such as comparing JSON content or HTTP status codes) promotes code organization and reusability. Test classes that implement these interfaces can leverage the default implementations, reducing code duplication and ensuring consistent assertion behavior across multiple test classes.

  3. Clarity and Readability: The use of interfaces with default methods can enhance the clarity and readability of unit tests. By providing well-named default methods in the interfaces, the intent and purpose of the assertions become more self-documenting, making the tests easier to understand and maintain.

The use of default methods in Java interfaces, as demonstrated in the unit test example, is a valid and practical approach when it comes to organizing and maintaining test code. It supports interface evolution, code organization, and code reusability. However, as with any programming feature, it should be used judiciously, and potential conflicts and interface design considerations should be carefully managed.

Impact of Default Methods on the Use of Abstract Classes

The introduction of default methods in Java interfaces has indeed influenced the role and necessity of abstract classes in Java programming. Abstract classes and interfaces in Java serve similar but distinct purposes: while abstract classes are used to provide a common base with some shared implementation, interfaces define a contract or capability without implementation details. Before Java 8, abstract classes were often used as a workaround to achieve some level of method implementation inheritance which was not possible with interfaces at the time.

However, with the introduction of default methods in interfaces in Java 8, the line between interfaces and abstract classes has somewhat blurred:

  1. Shared Implementations: Prior to Java 8, if you wanted to provide a shared implementation for certain methods, you would typically use an abstract class. Now, default methods in interfaces allow for shared implementations, reducing the need for abstract classes in many scenarios.

  2. Reduced Boilerplate Code: Default methods reduce the need for boilerplate code in implementing classes. In the past, similar functionalities had to be repeated in each subclass of an abstract class or were achieved through complex class hierarchies. Now, interfaces with default methods can provide a single, central place for such implementations.

  3. Enhanced Flexibility: Interfaces with default methods offer greater flexibility. A class can implement multiple interfaces but can only extend one abstract class. With default methods, a class can inherit behavior from multiple sources without the constraints of the single inheritance model.

  4. Design Philosophy: The design philosophy shifts from “is-a” (inheritance) to “has-a” (capability). This aligns with modern best practices in object-oriented design, where composition is favored over inheritance. Interfaces with default methods facilitate this approach by focusing on what an object can do rather than what it is.

  5. Abstract Classes Still Relevant: Despite these advantages, abstract classes remain relevant for certain use cases. They are still useful when you need to share state (fields) among various subclasses. Interfaces do not hold state and can only declare constants. Additionally, abstract classes are beneficial when the shared implementation should not be optional or needs to be protected from modification by the inheriting classes.

In conclusion, while default methods in interfaces have reduced some of the reliance on abstract classes by providing a means to share implementation code, they haven’t rendered abstract classes obsolete. The choice between using an interface with default methods and an abstract class depends on the specific requirements of the application and the design philosophy being followed.

Example of Interface Default Methods vs Interface-Abstract Implementations

Sure, let’s look at two examples to illustrate the usage of interfaces with and without default methods, and their implementation in an abstract class.

FlyingVehicle Interface without Default Methods

In this example, the FlyingVehicle interface will declare methods without providing default implementations. An abstract class AbstractFlyingVehicle will then implement this interface and provide the base implementation.


interface FlyingVehicle {
    void fly();
    void land();

Abstract Class Implementation:

abstract class AbstractFlyingVehicle implements FlyingVehicle {
    public void fly() {
        System.out.println("Basic flying mechanism");

    public void land() {
        System.out.println("Basic landing mechanism");

    // Additional functionalities common to all flying vehicles
    public void performPreFlightCheck() {
        System.out.println("Performing pre-flight check");

In this setup, any class extending AbstractFlyingVehicle will inherit the basic implementations of fly() and land(), and also has the additional method performPreFlightCheck().

abstract class AbstractFlyingVehicle implements FlyingVehicle {
    public void fly() {
        System.out.println("Basic flying mechanism");

    public void land() {
        System.out.println("Basic landing mechanism");

Now, let’s create a concrete class Helicopter that extends AbstractFlyingVehicle. The Helicopter class can use the provided implementations or override them with more specific behavior:

class Helicopter extends AbstractFlyingVehicle {
    public void fly() {
        System.out.println("Helicopter taking off");

    public void land() {
        System.out.println("Helicopter landing");

    public void hover() {
        System.out.println("Helicopter hovering");

In this example:

By using AbstractFlyingVehicle, we create a foundation for flying vehicles that can be extended and specialized by concrete subclasses. This approach is particularly useful when there are common functionalities or states that need to be shared among various subclasses, which is a typical use case for abstract classes.

FlyingVehicle Interface with Default Methods

Here, the FlyingVehicle interface will include default method implementations. This approach eliminates the need for an abstract class to provide base implementations.

Interface with Default Methods:

interface FlyingVehicle {
    default void fly() {
        System.out.println("Default flying mechanism");

    default void land() {
        System.out.println("Default landing mechanism");

    // Other flying-related methods can be added here

Concrete Class Implementation:

class BasicFlyingCar implements FlyingVehicle {
    // This class automatically inherits default implementations of fly() and land()
    // Additional specific methods for BasicFlyingCar can be added here

In this example, any class implementing FlyingVehicle will have the default implementations of fly() and land() unless it provides its own overrides. This approach provides greater flexibility and reduces the need for a hierarchy of abstract classes, simplifying the class design and structure.

Both examples illustrate the flexibility and choices Java offers in designing class hierarchies and interfaces, allowing developers to choose the approach that best fits their application’s architecture and requirements.


In conclusion, while Java does not support traditional multiple inheritance, it provides a powerful and flexible alternative through interfaces. This approach allows classes to inherit multiple sets of behaviors, encouraging code reusability and maintaining a clean, manageable code structure. Understanding and effectively utilizing interfaces, especially with the advent of default and static methods, can significantly enhance your Java programming capabilities.

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Java • Single Responsibility Principle
The Single Responsibility Principle (SRP), a fundamental concept within the SOLID principles, is crucial in Java programming. It dictates that each class should have only one reason to change, focusing on a single functionality or concern. This approach is particularly effective in Java, known for its robust object-oriented features, where SRP enhances maintainability, readability, and scalability of applications.
Java • Are Static Classes Things Of The Past?
Static classes have been a staple in the programming world for decades. Traditionally, a static class is one where all members and functions are static, meaning they belong to the class itself rather than any specific instance of the class. This makes static classes an efficient tool for grouping related functions and data that do not require object instantiation to be accessed.
Java • Interfaces Are Replacing Abstract Classes
The Java programming language, renowned for its robust structure and versatile capabilities, has witnessed a notable evolution in its fundamental components over the years. Among these, the role and functionality of interfaces and abstract classes have undergone significant changes, particularly with the introduction of new features in Java 8.
Java • Decoupling Arbitrary Objects Through Composition
In the dynamic landscape of software development, the concept of object decoupling plays a pivotal role in crafting efficient, maintainable, and scalable applications. At its core, object decoupling refers to the design approach where components of a program are separated in such a manner that they are independent, yet functionally complete. This separation ensures that changes in one part of the system minimally impact other parts, facilitating easier updates, debugging, and enhancement.
Java Primitives & Primitive Wrappers
Java, a robust and widely-used programming language, stands out for its efficient handling of data types. Central to its functionality are the Java primitives and their corresponding wrapper classes. This article delves into the essence of Java primitives, their types, and the distinction between primitive and non-primitive data types, including examples to illustrate these concepts.
Java • Primitive int vs Integer Best Practices
In Java, one of the foundational decisions developers must make pertains to choosing between primitive types and their corresponding wrapper classes, such as int and Integer. Both have their place in Java applications, and understanding their differences is paramount for writing efficient and effective code.
Java • Harnessing Static and Default Methods in Interfaces
The arrival of static and default methods in Java 8 marked a significant shift in interface capabilities, expanding their functionality and versatility in Java’s object-oriented ecosystem. This article explores the nuances of these features and their impacts on Java programming, simplifying complex concepts and illustrating their practical applications in modern software development.
Java Modern Collection Utilities
Java’s evolution has always been about simplifying complexity and enhancing efficiency. The collection utilities have undergone significant improvements since JDK 8, transitioning from the Collections utility class to the intuitive List.of(), Map.of(), and Set.of() methods.
Java • AssertJ vs Hamcrest Assertion Frameworks
When working with testing frameworks like JUnit or TestNG, selecting the right assertion framework can significantly enhance the readability of your test code and improve the overall quality of your tests. Two of the most popular Java assertion frameworks are AssertJ and Hamcrest.
Java • Unit Testing Best Practices
Unit testing is a fundamental aspect of software development, ensuring that each individual unit of source code is thoroughly examined and validated for correctness. With Java being one of the most widely used programming languages, it is crucial to adhere to the best practices for unit testing in Java to maintain the integrity and performance of the software.
Logback for Beginners
Logback, a Java-based logging framework within the SLF4J (Simple Logging Facade for Java) ecosystem, is the preferred choice in the Java community, serving as an enhanced successor to the popular Log4j project. It not only carries forward the legacy of Log4j but also brings to the table a quicker implementation, more comprehensive configuration options, and enhanced flexibility for archiving old log files.
Java • Modern Looping And Filtering with Stream API
Java has constantly evolved since its inception, presenting developers with numerous tools and methods to make coding more efficient and readable. Among these are modern techniques for looping and filtering data.
Java • Converting Strings To List
When it comes to working with Java, converting strings into lists is a common and essential operation that can significantly enhance your data processing capabilities. Whether you’re a seasoned programmer or just starting, mastering this technique will prove to be invaluable in your coding endeavors.
Java var Best Practices
Java, with each release and update, continually evolves to simplify the developer’s journey while preserving its core tenets of readability and robustness. One of the notable introductions in Java 10 was the var keyword. As with most new features, it sparked debates and questions regarding its efficacy and best practices.
URI vs URL in Java
In the realm of Java and web development, the terms URL and URI often emerge in discussions, leaving some in a quagmire of confusion. This article aims to elucidate the disparities between the two, elucidating their syntax, utilization in Java, and the nuances that set them apart.
Java vs JavaScript • Which Is In More Demand?
Java and JavaScript, despite their similar names, serve distinct purposes within the realm of software development. As both languages continue to evolve and find niches in the modern tech landscape, it’s crucial to understand their differences and their respective market demands.
Java Cloning Strategies
Object copying is a fundamental aspect of Java programming, finding relevance and utility in diverse contexts. Whether it’s creating independent copies of objects, maintaining object state, or avoiding unintended side effects, understanding efficient and reliable cloning strategies is essential.
Java Comprehensive Guide
Java is a versatile programming language that has gained widespread popularity for its platform independence and robustness. In this comprehensive guide, we will delve into the various aspects of Java programming, covering essential concepts, tools, and best practices.
Java • Converting Strings To Map
This article discusses converting a string of key-value pairs that are delimited by a specific character, known as a delimiter, into a Map in Java.
Maven vs Gradle
Maven and Gradle are two of the most popular build automation tools for Java-based projects. Both tools are designed to simplify the build process, manage dependencies, and facilitate project organization.
Java 19 Virtual Threads
In this article, we will provide an overview of virtual threads in Java and their use in concurrent programming. We will define what virtual threads are and how they differ from normal threads. Additionally, we will discuss the benefits of virtual threads over traditional concurrency approaches and provide code examples to illustrate the differences between the two.
Decoupling Domain Objects: Simplifying System Architecture
When you design an object-oriented system from top to bottom, sometimes the objects that represent the “domain” (what the system is about) don’t match the objects that represent the “entities” (what the system stores). To solve this problem, you can use a technique called “decoupling” to separate the layers of objects.
Java Final Modifier
In Java, the final keyword (also known as a modifier) is used to mark a variable, method, or class as immutable, meaning its value or behavior cannot be modified once it has been initialized.
Java Records
A Java record is a new feature introduced in Java 14 that allows developers to create a class that is primarily used to store data. A record is essentially a concise way to define a class that consists mainly of state (fields) and accessors (getters).
Java 17 Features
JDK 17, introduces several new features and improvements, including enhanced random number generators, new encoding-specific methods for the String class, and default classes for Java ciphers. It also removes the experimental AOT and JIT compilers, and introduces support for Sealed Classes and Records. These changes provide developers with more flexibility and control, making it easier to write efficient and secure Java applications.
Java Optional - Why Developers Prefer Optional Values
This article discusses the use of Java Optional to introduce optional values instead of null. We will deep dive into understanding why developers prefer the Optional class to clearly communicate an optional value as opposed to a vague null representation of a variable.
Java • Int to String Conversion Guide
In Java, often times the ability to return a string representing the specified integer is a common task. This article illustrates several mechanisms to convert int to a string in Java. In the opposite scenario, the means to resolve an integer representing the value of the specified String. The returned value is an Integer object that is the equivalent integer value of the argument string.
Java • Double to String Conversion | Beginner's Guide
Converting double to a String value in Java has been a typical task to do for software development. This article discusses the various ways on how to convert a double to a string in Java. While there are advantages in representing a double to its String object representation, the opposite task of converting a String object to a double can also be addressed. This document examines the reasons why conversions of double in Java are beneficial for beginners who are learning to develop in java.
Setting Java Compiler Version in Maven
This document demonstrates ways to set the java compiler version in maven via the maven.compiler.target property and the maven-compiler-plugin configuration section.
Getting Started with Maven Build System in Java Projects
The following page will illustrate how to get started with the maven build system in your java projects.  Use this guide as a reference when using Maven for the very first time.
Getting Started With Java
The following page will illustrate how to get started with the Java Programming Language.  In addition, this document provides an overview of how to install java and the environment variables you will need to set.  A hands-on approach illustrates how to compile and run your first Hello World java code.
Getting Started With Gradle
The following page will be an excellent guide with getting started with the gradle build system in your Java™ projects.  Use this guide as a reference when using Gradle as a build system for the very first time.