Understanding Inheritance in Java: Key Concepts & Benefits Explained

Inheritance​‍​‌‍​‍‌​‍​‌‍​‍‌ is among the major features of Object-Oriented Programming (OOP) which allows a class (a subclass or a child class) to have the same attributes and behavior (fields and methods) as another class (a superclass or a parent class). 

Such a mechanism not only supports the reuse of the code but also establishes the connection of different classes in most cases, hierarchically; thus, inheritance makes it possible for programmers to create generic classes and later specify them to more detailed classes. 

Foundational Concepts and Terminology of Inheritance in Java

Inheritance is the core idea behind Java's object-oriented programming model. Knowing the main terminology and the relations helps immensely to produce well-structured, reusable, and extendable code. Here are the essential concepts and vocabulary that you must be familiar ​‍​‌‍​‍‌​‍​‌‍​‍‌with:

Class

A​‍​‌‍​‍‌​‍​‌‍​‍‌ class is basically a design or a model that is used to make objects. It specifies the data (fields or attributes) and the behaviors (methods) of the objects that will be created from the class.

Object

An object is an instance of a class. It represents an entity with state (data stored in fields) and behavior (actions defined by methods).

Superclass (Parent Class, Base Class)

The superclass is the class that has its characteristics and behaviors passed down to the other classes. It is the base outline of the fields and methods that subclasses can either reuse or extend.

Subclass (Child Class, Derived Class)

The subclass is the class that inherits from another class (the superclass). It automatically acquires the fields and methods of the superclass, and can also introduce its own new functionalities or override inherited ones.

Fields and Methods

• Fields (also known as attributes or properties): Are the variables that store the data or the state of a ​‍​‌‍​‍‌​‍​‌‍​‍‌class.
• Methods: Functions or procedures that define the behaviors or actions a class can perform.

The extends Keyword

In Java, the extends keyword is used to establish an inheritance relationship between two classes. When a class is declared with extends, it inherits all non-private fields and methods from the specified superclass.

Example:

class Animal {
    void eat() {
        System.out.println("Eating...");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Barking...");
    }
}

Here, Dog is a subclass of Animal and inherits the eat() method.

IS-A Relationship

Inheritance in Java models an IS-A relationship, meaning the subclass is a type of the superclass.

Example:

A Dog IS-A Animal. Therefore, wherever an Animal is expected, a Dog can be used.

Access Modifiers and Inheritance

• public: The members are accessible from any other class.
• protected: The members are accessible by the subclasses (even in different packages) and also within the same ​‍​‌‍​‍‌​‍​‌‍​‍‌package.
• private: Members are not accessible outside the class in which they are declared.

When designing for inheritance, protected is often used for members intended to be accessible by subclasses.

Constructors and the super() Keyword

Constructors​‍​‌‍​‍‌​‍​‌‍​‍‌ are not passed down to subclasses. But a subclass is allowed to invoke a constructor of the superclass by using the super() keyword. It is a common practice to use this to initialize variables that are declared in the superclass.

Example:

class Animal {
    Animal(String name) {
        System.out.println("Animal name: " + name);
    }
}

class Dog extends Animal {
    Dog() {
        super("Dog");   // Calling parent constructor
    }
}

Single Inheritance

Java supports single inheritance, where a subclass inherits from only one superclass. This avoids ambiguity and simplifies the class hierarchy.

Summary Table

By mastering these key concepts and terms, you’ll have a strong foundation for understanding and applying inheritance in Java.

In​‍​‌‍​‍‌​‍​‌‍​‍‌ Java, inheritance is a concept where a class (subclass) gets the properties and methods of another class (superclass). This facilitates the reuse of code, as developers can create shared behavior only once and then apply it to different classes without the need to write the code ​‍​‌‍​‍‌​‍​‌‍​‍‌again. It also improves maintainability, because changes made in the superclass automatically apply to all subclasses.

Inheritance helps structure programs around natural IS-A relationships, such as a Car is a Vehicle or a Dog is an Animal. By extending a superclass, subclasses can inherit shared features while also adding or overriding methods to provide specialized behavior. This​‍​‌‍​‍‌​‍​‌‍​‍‌ results in a cleaner design, less duplication, easier updates, and more scalable Java applications. 

There are different inheritance types in Java that define relationships between classes. Inheritance helps in code reusability, reducing redundancy, and maintaining a clear hierarchy.

However, Java does not support multiple inheritance through classes to avoid the diamond problem. Instead, multiple Inheritance in Java can be achieved using interfaces. There are many examples of inheritance Java developers use, like single, multilevel, and hierarchical inheritance, along with interfaces for multiple behaviors.

1. Single Inheritance in Java

In​‍​‌‍​‍‌​‍​‌‍​‍‌ Java single inheritance program, a subclass is derived from a single superclass. The subclass is given the access to the methods and properties of the parent class.

Code Example:

class Animal {
    void eat() {
        System.out.println("Eating...");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Barking...");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.eat();  // Inherited method from Animal
        myDog.bark(); // Method from Dog class
    }
}

Explanation:

Here,​‍​‌‍​‍‌​‍​‌‍​‍‌ we have two classes in the program, Animal and Dog. The Dog class goes beyond the Animal class, so it gets the methods from Animal. The Animal class has a method eat() that outputs "Eating...", and the Dog class has a method bark() that outputs "Barking...". In the main method, an object of the Dog class named myDog is created. As Dog is a subclass of Animal, myDog can invoke both eat() (from Animal) and bark() (from Dog). This is a basic example of inheritance in Java where a subclass can access and extend the features of its ​‍​‌‍​‍‌​‍​‌‍​‍‌superclass.

Output:

Eating...
Barking...

2. Multilevel Inheritance in Java

In a multilevel inheritance program in Java, a class inherits from a class that is itself a subclass of another class. This creates a chain of inheritance.

Code Example:

class Animal {
    void eat() {
        System.out.println("Eating...");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Barking...");
    }
}

class Puppy extends Dog {
    void weep() {
        System.out.println("Weeping...");
    }
}

public class Main {
    public static void main(String[] args) {
        Puppy myPuppy = new Puppy();
        myPuppy.eat();  // Inherited from Animal
        myPuppy.bark(); // Inherited from Dog
        myPuppy.weep(); // Defined in Puppy
    }
}

Explanation:

• Puppy inherits from Dog, which inherits from Animal.
• Puppy can access methods from both Animal and Dog.
  This demonstrates how properties are passed through multiple levels of inheritance.

Output:

Eating...
Barking...
Weeping...

3. Hierarchical inheritance in Java

In hierarchical inheritance in Java program, multiple subclasses inherit from a single parent class.

Code Example:

class Animal {
    void eat() {
        System.out.println("Eating...");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println("Barking...");
    }
}

class Cat extends Animal {
    void meow() {
        System.out.println("Meowing...");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.eat();  // Inherited from Animal
        myDog.bark(); // Defined in Dog

        Cat myCat = new Cat();
        myCat.eat();  // Inherited from Animal
        myCat.meow(); // Defined in Cat
    }
}

Explanation:

• Dog and Cat both inherit from Animal, so they can use eat().
• Each subclass has its own unique method (bark() for Dog, meow() for Cat).
• This type of inheritance is useful when multiple classes share common behavior.

Output:

Eating...
Barking...
Eating...
Meowing...

4. Multiple Inheritance in Java(Using Interfaces)

Java does not allow multiple inheritance in classes because of the possibility of ambiguity (the diamond problem). Nevertheless, the Java multiple inheritance example is possible by using ​‍​‌‍​‍‌​‍​‌‍​‍‌interfaces.

Code Example:

interface Engine {
    void startEngine();
}

interface Wheels {
    void rotateWheels();
}

class Car implements Engine, Wheels {
    public void startEngine() {
        System.out.println("Engine started...");
    }

    public void rotateWheels() {
        System.out.println("Wheels are rotating...");
    }
}

public class Main {
    public static void main(String[] args) {
        Car myCar = new Car();
        myCar.startEngine();  // Implemented from Engine
        myCar.rotateWheels(); // Implemented from Wheels
    }
}

Explanation:

• Multiple inheritance through classes is not allowed, but Java allows it using interfaces.
• Car implements both the Engine and Wheels, inheriting behaviors from both interfaces.
• Each interface defines a specific behavior, and the Car class implements those methods.

Output:

Engine started...
Wheels are rotating...

5. Hybrid inheritance in Java (Using Interfaces)

Combining two or more inheritance types (such as single and multiple) is known as hybrid inheritance in Java. Java permits hybrid inheritance through interfaces but not through classes.

Code Example:

interface Animal {
    void eat();
}

class Mammal {
    void breathe() {
        System.out.println("Breathing air...");
    }
}

class Dog extends Mammal implements Animal {
    public void eat() {
        System.out.println("Dog is eating...");
    }

    void bark() {
        System.out.println("Dog is barking...");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.eat();    // Implemented from Animal
        myDog.breathe(); // Inherited from Mammal
        myDog.bark();   // Defined in Dog
    }
}

Explanation:

• Dog​‍​‌‍​‍‌​‍​‌‍​‍‌ extends Mammal (class) and implements Animal (interface), thus utilizing a mixture of single inheritance and multiple inheritance.
• It gets breathe() from Mammal and eat from Animal, thus showing hybrid inheritance.

Output:

Dog is eating...
Breathing air...
Dog is barking...

Quick Recap So Far:

• Single Inheritance: One superclass from which one subclass is derived is the most basic and well-known kind.
• Multilevel Inheritance: A series of inheritance (A → B → C) that allows traits to be passed via many levels is known as multilevel inheritance.
• Hierarchical Inheritance: Several subclasses deriving from the same superclass, thus sharing common behavior.
• Multiple Inheritance (via Interfaces): One class may implement several interfaces to inherit several behaviors.
• Hybrid Inheritance (via Interfaces): The use of single, multilevel, and interface-based multiple inheritance in combination. 

A subclass can offer a specific version of a method that is already specified in its superclass using the method overriding feature of inheritance in Java. When a method in the child class has the same name, return type, and parameters as a method in the parent class, it overrides the parent method.

Key Points about Method Overriding

• Same Method Signature: The name, return type, and parameters of the overriding method must match those of the parent class method.
• @Override Annotation (Recommended): The @Override annotation ensures that the method is correctly overriding a superclass method and helps catch errors at compile time.
• Only instance methods are capable of being overridden: Static methods cannot be overridden; instead, they are hidden.
• Access Modifiers Rule: A protected method cannot be overridden as private, for example, and the overriding method cannot have a higher restricted access modifier compared to the overridden method.
• Final Methods Cannot Be Overridden: If a method is declared final, it cannot be overridden.
• Constructors Cannot Be Overridden: Constructors are not inherited, so they cannot be overridden.

Basic Example of Method Overriding

// Parent class
class Animal {
    void makeSound() {
        System.out.println("Animal makes a sound");
    }
}

// Child class
class Dog extends Animal {
    @Override
    void makeSound() {
        System.out.println("Dog barks");
    }
}

// Main class
public class Main {
    public static void main(String[] args) {
        Animal myAnimal = new Animal();
        myAnimal.makeSound(); // Calls the Animal class method

        Dog myDog = new Dog();
        myDog.makeSound(); // Calls the overridden method in Dog class
    }
}

Explanation:

• The Dog class overrides the makeSound() method of the Animal class.
• The overridden function in Dog is called rather than the one in Animal once we create a copy of Dog and use makeSound().

Output:

Animal makes a sound
Dog barks

Using super in Method Overriding

The super keyword allows access to the parent class's methods that have been overridden in the subclass. It is useful when we want to extend the functionality of a method rather than completely replacing it.

Example: Calling the Parent Method Using super

class Animal {
    void makeSound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    @Override
    void makeSound() {
        super.makeSound();  // Calls the parent class method
        System.out.println("Dog barks");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.makeSound();
    }
}

Output:

Animal makes a sound
Dog barks

Summary

Method overriding allows a subclass to redefine a method already defined in its superclass, enabling more specific or customized behavior. It works only when the method name, return type, and parameters match exactly. Using @Override helps ensure accuracy, while rules like "no overriding of static, final, or constructor methods" maintain class integrity. The super keyword lets a subclass call the parent version of the method, making it easy to extend existing behavior rather than replace it entirely.

In Java, there are three ways to limit change using the final keyword:

1. Final Variables → Values cannot be changed once assigned.
2. Final Methods → Can't be inherited or expanded by another class.
3. Final Classes → Cannot be extended (inherited) by another class.

When used in Inheritance in Java, the final keyword prevents subclass modifications to a method or an entire class.

1. Declaring a Class as final (Prevents Inheritance)

When a class is marked as final, it cannot be extended by another class. This is useful when you want to create an immutable class or prevent modifications in subclasses.

Example: final Class Preventing Inheritance

final class Animal {
    void makeSound() {
        System.out.println("Animal makes a sound");
    }
}

// Compilation error: Cannot extend a final class
class Dog extends Animal {  
    void makeSound() {
        System.out.println("Dog barks");
    }
}

Compilation Error:

error: cannot inherit from final Animal
class Dog extends Animal {
                                ^

2. Declaring a Method as final (Prevents Overriding)

A final method cannot be overridden in a subclass. This is useful when you want to fix a method’s implementation to prevent modifications.

Example: final Method Preventing Overriding

class Animal {
    final void sound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    // Compilation error: Cannot override a final method
    void sound() {
        System.out.println("Dog barks");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog myDog = new Dog();
        myDog.sound(); // This line will not compile
    }
}

Quick Note

The​‍​‌‍​‍‌​‍​‌‍​‍‌ final keyword is the main tool for managing inheritance in Java. It allows the developer to safeguard the core logic from being changed, avoid subclass that behaves differently unintentionally, and facilitate the development of safe, reliable, and consistent class structures. Apply it carefully, just in case you really want to prohibit further extension or ​‍​‌‍​‍‌​‍​‌‍​‍‌overriding.

It​‍​‌‍​‍‌​‍​‌‍​‍‌ is possible that inheritance in Java usage will lead you to some pits which help your code harder to maintain and understand. By following best practices, you not only avoid these issues but also build more dependable and flexible applications. ​‍​‌‍​‍‌​‍​‌‍​‍‌

Common Pitfalls

1. Excessive Subclassing and Deep Hierarchies

Creating long chains of inheritance (e.g., A → B → C → D) makes code more difficult to follow and maintain. Deep hierarchies can introduce hidden dependencies and increase the risk of bugs when changes occur in parent classes.

2. Improper Use of Inheritance

Inheritance should model an "is-a" relationship, not just be used for code reuse. Using inheritance where a "has-a" or "uses-a" relationship is more appropriate can lead to confusing and fragile designs.

3. Tight Coupling Between Superclass and Subclass

Subclasses often depend heavily on the implementation details of their superclasses. If the superclass changes, it may unintentionally break subclasses, making updates risky and error-prone.

4. Ignoring Java’s Limitations on Multiple Inheritance

Java prohibits repeated inheritance through classes to prevent ambiguity (the diamond problem). Trying to forcibly do multiple inheritance may bring about complicated systems. Therefore, it is better to use interfaces to get multiple behaviors.

5. Overriding Methods Incorrectly

Failure of the @Override annotation or mismatching method signatures can lead to such subtle bugs that the overriding may not actually be done.

6. Exposing Internal State with Inappropriate Access Modifiers

Using public or even protected fields without careful design can expose internal state and break encapsulation, making maintenance harder.

7. Not Preventing Unwanted Inheritance or Overriding

If the final keyword is not used on the important classes or methods, the extension or modification of them will be allowed thus there may be the appearance of security or logic ​‍​‌‍​‍‌​‍​‌‍​‍‌errors.

Best Practices

1. Prefer Composition Over Inheritance

Whenever possible, use composition (having classes reference other classes) instead of inheritance. This approach is more flexible and reduces tight coupling.
Example:
Instead of class Car extends Engine, use class Car { private Engine engine; }.

2. Keep Inheritance Hierarchies Shallow

Limit the depth of your inheritance trees. Shallow hierarchies are easier to understand, test, and maintain.

3. Use Interfaces for Multiple Behaviors

If a class needs to exhibit multiple behaviors, implement interfaces rather than extending multiple classes.

4. Document Class Relationships

Clearly comment on why inheritance is used and what relationships exist between classes. This helps future maintainers understand your design.

5. Use the @Override Annotation

Always use @Override when overriding a superclass method. This ensures compile-time checking and makes your intent clear.

6. Restrict Inheritance with final When Needed

Mark classes or methods as final if you want to prevent further extension or modification. This is especially useful for security or to preserve core logic.

7. Control Access with Proper Modifiers

Use private for internal fields whenever possible, and protected only when subclasses genuinely need access.

Bottom Line:

By keeping these pitfalls and best practices in mind, you’ll write inheritance-based Java code that is cleaner, safer, and more maintainable.

1. Code Reusability
   You don’t need to write the same code again and again. A subclass can reuse methods and variables from its parent class.
2. Improves Code Organization
   It helps structure your code by grouping common behavior in a base class, making it easier to manage and understand.
3. Supports Polymorphism
   Inheritance allows objects to be treated as instances of their parent class, enabling flexible and dynamic method execution.
4. Easy Maintenance
   If a bug or change is needed in the shared logic, you can update it in one place (the parent class) instead of every individual class.
5. Encourages Logical Hierarchy
   It helps you build a natural relationship between classes, for example, Dog is an Animal.

1. Tight Coupling Between Classes
   Subclasses depend on parent classes. If the parent changes, it may break the child classes.
2. Increased Complexity
   Deep inheritance chains can make the code harder to follow, especially when debugging.
3. Less Flexibility
   Once a class inherits another, changing the structure or behavior later may become difficult.
4. Misuse of Inheritance
   Inheritance should model "is-a" relationships. Using it for code reuse without proper planning can lead to poor design.
5. Difficult to Understand for Beginners
   Understanding how data flows across multiple inherited classes can be confusing for those new to programming.

Inheritance​‍​‌‍​‍‌​‍​‌‍​‍‌ in Java is not just a concept; it is one of the core instruments, which are utilized in numerous programs to attain the objectives of code reusability, maintainability, and logical class hierarchies. 

Here are some real-life situations and samples of where inheritance is ​‍​‌‍​‍‌​‍​‌‍​‍‌mandatory: 

1. Graphical User Interface (GUI) Frameworks

Inheritance usage is the main feature of Java’s widely used GUI frameworks, such as Swing and JavaFX. To make the components common (buttons, labels, and panels) of the GUI easily accessible, the frameworks introduce the base classes. Now the developers are free to extend these base classes in order to bring out the components that meet the shared behaviors and have the added features of the new components.

Example:

In the case of Swing, AbstractButton is the class from which JButton extends. The latter extends JComponent. The hierarchy thus allows all buttons to inherit common functionality (like rendering and event handling) while enabling customization.

Why it matters:

With the help of this type of framework, developers can produce complex user interfaces more quickly. Additionally, it enables them to maintain consistency across the components and reuse the code.

2. Modeling Real-world Hierarchies

Inheritance is perfect for capturing real-world relationships in programming. For the sake of clarity, here are some examples that explain it better:

• Employee Management Systems:
  The single Employee class with all its common features may become a family of such classes as Manager, Developer, or Intern by each adding special features or behaviors. 
• E-commerce Platforms:
  Firstly, the Product class can be extended by the classes of Book, Electronics, and Clothing, respectively. This will make it possible for the products to have common features (like price, SKU) and at the same time have their unique attributes (like author, warranty). 
• Transportation Systems:
  The Vehicle superclass can have its doors open for extension by the classes of Car, Truck, and Motorcycle. All subclasses will be inheriting the common features (for instance, speed or fuel type) and will also be able to add features specific to them. 

Why it matters:

Such an approach reproduces the relationships of the real world, thus making code not only human-like, reusable, and less error-prone but also easier maintainable.

3. Frameworks and Libraries

A lot of open-source Java libraries and Java APIs have architectures that are extensible by inheritance. For example, the Java Collections Framework defines abstract classes like AbstractList and AbstractMap, which can be extended to create custom data structures.

Why it matters:

Developers can develop high-quality, extensively tested, and dependable code by using inheritance, which saves them time and effort while guaranteeing that their work is consistent throughout the project.

4. Common Functionality in Enterprise Applications

In large-scale Java applications, inheritance is frequently employed to gather and reuse common features such as logging, security checks, or data access logic in one place. For instance, a web application's base BaseController class may have methods for authentication that are shared among all subclasses from which the specific controllers are derived.

Why it matters:

It reduces the redundancy that exists between different parts of the program, guarantees that the behavior is uniform throughout the program, and also makes future updates smoother and easier. Additionally, all subclasses will immediately reflect any modifications made to the original class.

5. Polymorphism and Code Flexibility

The concept of inheritance is the source of polymorphism. It permits the treating of objects as members of their parent class. For the instance, a method that deals with a list of Animal entities can call for any subclass (Dog, Cat, etc.) This is what makes the program extensible and flexible.

Summary:

Java programmers can take advantage of the inheritance feature to come up with applications that are not only robust, easy to maintain, and scalable but also close to the structures and relationships of the real ​‍​‌‍​‍‌​‍​‌‍​‍‌world.

Inheritance in Java enhances code reuse, improves class structuring, and enables polymorphism. Understanding its various forms and best practices helps in designing scalable and maintainable applications. By leveraging inheritance properly, developers can create robust object-oriented solutions efficiently.

Points to Remember 

1. Inheritance​‍​‌‍​‍‌​‍​‌‍​‍‌ is one of the features through which code reuse is possible. Besides that, inheritance hierarchies are possible, which means that subclasses can rely on the shared functionality of a superclass.
2. Java allows single inheritance for classes and multiple or hybrid inheritance only by interface, so that there is no ambiguity.
3. Method overriding + polymorphism gives the power of inheritance, which can be used for dynamic behavior at runtime.
4. If inheritance is only used for true IS-A relationships, then that is the correct use of inheritance; otherwise, composition should be used to avert tightly coupled code and complex code.
5. Best practices matter: keep hierarchies shallow, use @Override, avoid unnecessary inheritance, and protect important methods/classes with final.

1. What is Inheritance in Java?

Inheritance in Java is an essential feature of Object-Oriented Programming, through which a child or subclass inherits the properties and functionalities of a parent or superclass. First​‍​‌‍​‍‌​‍​‌‍​‍‌ and foremost, this functionality intends to simplify the reusing of code, set up the correct relationships between classes, and manage the program flow in a coherent and rational way.

2. What are the different types of Inheritance in Java?

Java mainly features single inheritance, where one subclass inherits the attributes and methods of one parent. For multilevel inheritance, a class inherits from another subclass, thus creating a chain. In hierarchical inheritance, several subclasses inherit from the parent class. To avoid ambiguity, Java does not allow multiple inheritance using classes but permits multiple and hybrid inheritance via interfaces.

3. Why does Java not support Multiple Inheritance through classes?

Java doesn't support multiple inheritance with classes to eliminate the possibility of contradictory issues when two unrelated parent classes possess a method with the same name. This situation - the so-called "diamond problem" - leads to an indeterminate state as to the choice of method one should inherit. To tackle it, Java repurposes a similar construct - interfaces - making a class free to follow more than one without the risk of a clash.

4. Mention the difference between Method Overloading and Method Overriding in Java

Method overloading is a feature of a single class where multiple methods with similar names but different parameters are defined, thereby enabling different usages of the methods depending on the input.

On the other hand, in method overriding, the subclass redefines a method that already exists in the parent class to offer its own version. Method overriding actually helps a subclass alter the inherited behavior according to its requirements, but at the same time keeps the method signature intact.

5. How does the super keyword work in inheritance?

The super keyword in Java acts as a reference to the superclass and thereby imports one or more attributes of the latter lineage. With the help of this carrier, one may be able to override the parent class method in the child and yet have a call to the original method. In addition, calling a parent constructor with the super operator assists in loading the attributes that are made available through inheritance, thus ensuring that instantiations flow orderly in the hierarchy.

6. What is the main purpose of the final keyword in Inheritance?

The final keyword serves the purpose of forbidding changes in inheritance. The class, once marked as final, is not allowed to be inherited by any other class, thus making sure that its behavior is not altered by any subclass. A method declared as final cannot have its implementation changed in a subclass.

7. What are some best practices when using Inheritance in Java?

While you are working with inheritance, it is good to keep in mind that a better option than inheritance would be composition, if only for the reason that it is more versatile and does not create strongly-coupled classes. Keeping the inheritance hierarchy shallow improves code readability and maintainability. Using interfaces instead of deep inheritance structures helps achieve multiple behaviors without complexity.