Given that the SOLID principles offer more maintainability and extensibility to your project, I'd prefer interfaces over inheritance. We’ll introduce the pattern, a simplifying abstraction over data storage, allowing us to decouple our model layer from the data layer. Prefer composition to inheritance. The sentence is directed towards people at stage 2 in the hype cycle, who think inheritance should be used everywhere. There are however a number of projects around that can automate this either at compile time (via a pre-processor) or at runtime eg jmixin. Classes and objects created through composition are loosely coupled, which. Composition vs Inheritance in the Semantic Web. a = 5; // one less name. Viewed 7k times. These are just a few of the most commonly used patterns. In our case, we could imagine a BurgerMenuManager class that provides all the needed methods to setup the burger menu icon and interact with it,. In the implementation of this pattern, we prefer composition over an inheritance - so that we can reduce the overhead of subclassing again and again for each. ” Scott Oakes said that to me, Reply reply ijgowefk • This can be written more clearly as Prefer interfaces and composition over inheritance As written, it sounds like Pefer composition over. – jscs. g 1. In this article, I discussed why you should prefer composition over inheritance, looked at the repository and DTO patterns, and compared two options for initializing lazily fetched associations in the business layer to avoid the Open Session in View anti-pattern. The new class is now a subclass of the original class. Reasons to Favour Composition over Inheritance in Java and OOP: The fact that Java does not support multiple inheritances is one reason for favoring. Interface-based Inheritance. This is why, there is a rule of thumb which says: Prefer composition over inheritance (keeping in mind that this refers to object composition. ”. The composition can offer more explicit control and better organization in such scenarios. As for composition over inheritance, while this is a truism, I fail to see the relevance here. Why prefer composition instead of heirship? What trade-offs are there required each approach? And the converse question: when ought I choose inheritance instead of composition? Stack Overflow. If you'll read their full argumentation, you'll see that it's not about composition being good and inheritance bad; it's that composition is more flexible and therefore more suitable in many cases. Composition over inheritance! A lot of times developers look at principles like SOLID and forget the basic Composition over inheritance principle. 5. 2. ‘Behavior’ composition can be made simpler and easier. Composition vs. Prefer Composition over Inheritance. In the same fashion, one may think that a ThickBorder is-a special Border and use inheritance; but it's better to say that a Border has-a width, hence preferring composition. The "is-a" description is typically how an inheritance relationship is identified. Also, is it not possible to have the generic (isInteger etc) methods implemented in the interface Validator and marked finalGoogle "is a, has a" inheritance and composition for an overview on when to use each. Again, now it's clear where that Component is going. I had been confused same as you until I found this explanation: Inheritance is Bad: Code Reuse Great example where author explain inheritance based on example typically used to show why inheritance is "great". -- Why I mostly prefer composition over inheritance on inheritance problem on benefit of composition over inheritance. You must have heard that in programming you should favor composition over inheritance. If you can justify the relationship in both directions, then you should not use inheritance between them. To understand why " prefer composition over inheritance", we need first get back the assumption omitted in this shortened idiom. Similarly, a property list is not a hash table, so. Unlike interfaces, you can reuse code from the parent class in the child class. Inheritance. Composition is preferred over deep inheritance in React. Composition: Composition is the technique of creating a new class by combining existing classes. As always, all the code samples shown in this tutorial are available over on GitHub. From Effective Java 2nd Edition, Item 16: Favor composition over inheritance: There are a number of obvious violations of this principle in the Java platform libraries. Composition-based solutions break up a problem into distinct responsibilities and encapsulate the. Inheritance is used when there is a is-a relationship between your class and the other class. If the client needs access to everything JButton provides (dubious) you now have to create a bunch of boilerplate. Prefer Composition over Inheritance while Reusing the Functionality Inheritance creates dependency between children and parent classes and hence it blocks the free use of the child classes. And you probably mostly should - "prefer composition over inheritance". NET Prefer Composition Over Inheritance is an important tenet of Object oriented programming, but what's so bad about. The main difference between inheritance and composition is in the relationship between objects. Single inheritance rules out using inheritance for "has-a" relationships like those in the cars example above. If this instruction is followed, one of the biggest features of inheritance is irrelevant: inherited. Composition at least you can freely refactor if you need to. What advantages does composition have over inheritance? Coupling and Cohesion Ideally, the objects in our system have high cohesion (i. Also, when you change a class, it may have unexpected side-effects on inheriting objects. Unless your library has a compelling reason to make forced inheritance more natural/effective, then you should assume that people will consume your library via composition. The point in the comments about using interfaces for polymorphism is well made. You really need to understand why you're doing it before you do it. At first, it provided dynamic polymorphism. "X inherits Y" implies that "X is a Y", so it can be useful in cases where that statement is technically true (for example, "a square is a rectangle"). One of the issue with inheritance is when you get a diamond structure. Composition over inheritance (or composite reuse principle) in object-oriented programming (OOP) is the principle that classes should achieve polymorphic behavior and code reuse by their composition (by containing instances of other classes that implement the desired functionality) rather than inheritance from a base or parent. First, justify the relationship between the derived class and its base. In the answer to this question and others, the guidance is to favor composition over inheritance when the relationship is a "has-a", and inheritance when "is-a". Prefer composition over inheritance as it is easier to modify later. One score (minus five) years ago, in the age of yore and of our programming forefathers, there was written a little book. 1. Classes and objects created through inheritance are tightly coupled, changing the parent (or superclass) in an inheritance relationship can cause unwanted side effects on the subclass. dev for the new React docs. E. It just means that inheritance shouldn't be the default solution to everything. Why prefer structure instead of inheritance? About trade-offs are there for each approach? And the converse question: when should I choose inheritance instead of composition? Stack Overflow. Goを勉強している中で、「Composition over inheritance」という概念が出てきました。ちゃんと理解していなかったので、ここで改めて掘り下げます。 ちゃんと理解していなかったので、ここで改めて掘り下げます。 Communicating clearly with future programmers, including future you. Cars and trucks both have steering and acceleration, but a truck isn't a car, and shouldn't inherit behavior from it just because some of the implementation is shared. Official source : flutter faq. 8. OOP allows objects to have relationships with each other, like inheritance and aggregation. But what if several classes do have some common attributes? Do you need to extract a base class for them? When inheritance is. You do composition by having an instance of another class C as a field of your class, instead of extending C. Object composition can be used as an alternative or a complement to inheritance, depending on the situation and the design goals. 8. Assume that you have started a project and you decided to use VIPER as project architecture. Therefore, it's always a good idea to choose composition over inheritance. In that case, why inheritance is provided as the one of the main concepts. That means that insteed of making use of inheritance, we’ll make our UIViewController contain / be composed of inner classes that provide the behavior. For example, you can define a class called Animal, with attributes like name, age, and. I checked Qt,. Additionally, if your types don’t have an “is a” relationship but. The question was "is it still as true that one should prefer composition over inheritance in such situations ?". If you take the general approach of "Prefer Composition over Inheritance", you may find out that one or both of the classes shouldn't be actually "Inherited" anyway. Yes, the main purpose is code reuse, but it's a complex and inflexible way of doing it. This echoes the advice to prefer composition over inheritance and to keep inheritance hierarchies shallow, with few layers of sub-classing. The new class is now a subclass of the original class. H2CO3 February 5, 2022, 6:49am 3. If needed later, make them later. Inheritance vs. Favor object composition over class inheritance. However, in object-oriented design, we often hear the advice to prefer composition over inheritance to achieve. The new class has now the original class as a member. And I read few times, you should prefer composition. When you use composition, you are (as the other answers note) making a "has-a" relationship between two objects, as opposed to the "is-a" relationship that you make when you use inheritance. When we develop apps to React, there are a few main reasons why we should go with composition over inheritance. When in doubt, prefer composition over inheritance. edited Dec 13, 2022 at 23:03. How can we refactor "inheritance code reuse" into composition and still be able to keep a polymorphic approach?. Let's say you have a screen where you're editing a list of Users. Should We Really Prefer Composition Over Inheritance? In short? Yes — but not in the way I used to think. For example, rather than. When you use composition, you are (as the other answers note) making a "has-a" relationship. Composition in JavaScript is implemented through concatenative. ago. You still get code reuse and polymorphism through it. Programming is as much an art as a science. Prefer composition over mixins for complex behaviors: If the desired behavior involves complex composition or multiple interacting components, consider using composition (i. In that case, the following is possible (with Eclipse): Write a class skeleton as follows: class MyClass implements XXXInterface. The composition is achieved by using an instance variable that refers to other objects. This is where the age-old design pattern of composition over inheritance comes into the picture. Prefer composition over inheritance as it is more malleable / easy to modify later, but do not use a compose-always approach. So which one to choose? How to compare composition vs inheritance. Use aggregation. , combining multiple classes) instead of relying solely on mixins. 2: Repository Pattern. It very quickly becomes a tree that reaches out to all different directions. You must have heard that in programming you should favor composition over inheritance. A good example where composition would've been a lot better than inheritance is java. Changing a base class can cause unwanted side. There are two benefits of inheritance: subtyping and subclassing Subtyping means conforming to a type (interface) signature, ie a set of APIs, and one can override part of the signature to achieve subtyping polymorphism. Ultimately, it is a design decision that is. That's why it exists. From a programming standpoint, most object-oriented programming languages allow inheriting from only one class (i. It mostly boils down to limiting use of extend and super, and still preferring composition over inheritance. When an object of a class assembles objects from other classes in that way, it is called composition. JimchaoTry reading through a few answers on Prefer composition over inheritance? As a rule of thumb try out this: if inheritance would result in more than 3 levels of hierarchy, use composition if you have something that matches the strategy pattern, use inheritance always prefer composition (try it first)As the saying goes: prefer composition over inheritance. eg:Why prefer composition instead of inheritance? What trade-offs were there to jeder approach? And the converse question: when should I choose inheritance instead of arrangement? Stack Overflow. The composition can be used to achieve code reuse without creating complex inheritance hierarchies. Antipattern: inheritance instead of composition. Inheritance is about the relationship of class and class. In my opinion…Composition. Inheritance does not break encapsulation. Be very careful when you use inheritance. util. Use aggregation. A Decorator provides an enhanced interface to the original object. There is a principle in object-oriented design to prefer composition over inheritance. In general I prefer composition over inheritance. e. There have been two key improvements made to interfaces in Java 8 and above, that. Composition and inheritance are two ways that you can use to build an object. Composition at least you can freely refactor if you need to. e. The Second Approach aka Composition. 1107. So let’s define the below interfaces:I think programmers prefer composition over inheritance because most software contains complex objects that are difficult to model with inheritance. 1 Answer. some of the reasons cited for this are. Inheritance doesn’t have this luxury. An interface (the C# keyword kind) is for giving common behavior to unrelated classes and then handle objects polymorphically. Inheritance has advantages but comes with many problems. 🚨 IMPORTANT:1 Year Free Hosting: code KYLE for an additional $50Object oriented programming has been around for. Much like other words of wisdom, they had gone in without being properly digested. OOP: Inheritance vs. Without knowing what both classes do or represent, it is impossible to decide whether one 'is a' subtype of the other, but let me remark that in "Effective Java", Joshua Bloch recommends to prefer composition over inheritance in most situations, since inheritance provides your new class with an interface that may be too large, or out of its. Composition is a "has-a". This blog goes over the topic of what is composition, what is inheritance and why composition is a better fit in most case. The saying is just so you have an alternative and compact way to learn. Some reasons: The number of classes increases the complexity of the codebase. –Widgets should be entirely agnostic about the type of that child. In this case, MasterChecker (correctly) composes the various concrete checkers, as your advice recommended. Conclusion. Don’t use is or similar checks to act differently based on the type of the child. Difference between. Inheritance is among the first concepts we learn when studying object-oriented programming. In the world of Object-Oriented Programming (OOP) you may have heard the statement 'favour composition over inheritance'. Inheritance can get messy. Follow. If I was working in an existing codebase with a traditional classy architecture, I'd certainly prefer to use class instead of the weird hoop-jumping we had to do in ES5 and older. Decorator pattern is an example of this. It gives a code example of inheritance first, and then a code example of composition. class Car may have an Engine member (composition), but may be (i. With composition, it's easy to change behavior on the fly with Dependency Injection / Setters. For example, a stack is not a vector, so Stack should not extend Vector. In object-oriented programming, inheritance, and composition are two fundamental techniques for creating complex software systems. While the consensus is that we should favor composition over inheritance whenever possible, there are a few typical use cases where inheritance has its place. Composition is often combined with inheritance (are rather polymorphism). Inheritence uses the java compiler's type system to implicitly include code from elsewhere, with delegation you explicitly implement the callout. Prefer Composition Over Inheritance is an important tenet of Object oriented programming, but what's so bad about Inheritance? In this video, we'll explore s. The car has a steering wheel. Follow answered Apr 27, 2009 at 20:25. Inheritances use when Portfolio A is a type of List but here it is not. The primary issue in composition vs inheritance is that the programming world has begun to think of these two concepts as competitors. Enroll for free. This is achieved by creating an instance of the existing class within the new class and delegating the required functionality to the instance. Strategy Pattern. Hello proggit, I've heard from quite a few places lately to prefer composition to inheritance (last time was from…Sử dụng Composition để thay thế Inheritance. It was difficult to add new behaviour via inheritance since the. , combining multiple classes) instead of relying solely on mixins. Normally I prefer composition over inheritance, but given that this ensures a consistent set of IDs and allows for a common stream for a limited number of types, I'm not too sure why it wouldn't. Widgets are built out of smaller widgets that you can reuse and combine in novel ways to make custom widgets. The call C(). Composition works with HAS-A relationship. I'm currently reading 'Head first design patterns' and I already have a few questions on the first chapter of the book. Với nguyên lý Composition over Inheritance ta gom các phương thức chung vào một đối tượng riêng sau đó thực hiện tham chiếu các đối tượng này vào đối tượng mới được khởi tạo. dead_alchemy • 14 hr. Composition over inheritance is the principle that classes should achieve polymorphic behavior and code reuse by their composition (by containing instances of other classes that implement the desired functionality) rather than inheritance from a base or parent class. The purpose of using composition instead of inheritance is so that you can only delegate the behaviors you want to delegate. What to prefer: Inheritance or Object Composition? The “Gang of Four” write in Design Patterns we should prefer composition over inheritance whenever we can because of the decoupled principle. It's called a trait object, and it's not the same as generics. The big advantage is that it doesn't require delegation to. This site requires JavaScript to be enabled. None provides association. Why you should favor composition over inheritance. Composition has always had some advantages over inheritance. You want to write a system to manage all your pizzas. – Blake. It also gives the developer more power over how this progress bar works. 5. So for your specific case, it seems that your initial directory structure is fine. React recommends use of Composition over Inheritance, here is why. Usually it implies the opposite. Although it is not suited to all software designs there are situations where it is difficult to deny it's utility over interfaces, composition and similar OO techniques. It is but to refactor an inheritance model can be a big waste of time. Almost everything else could change. The biggest point of confusion and contention seems to be composition versus inheritance, often summarized in the mantra “ favor composition over. children, we can separate code in the separated places. So in your case, using composition for attributes like wings and legs makes perfect sense, but Bird, Cat and Dog ARE animals - they don't "have" an animal (well, they all have fleas but that's another topic) - so they should inherit from Animal. Note that the phrase is to favor composition over inheritance. Yes, (novice) developers need to be urged away from overusing inheritance, but that does not invalidate that there are use cases for inheritance. e. The subclass uses only a portion of the methods of the superclass. Teach. Notice that composition is harder. Favor 'object composition' over 'class inheritance'. Favor composition over inheritance is one of the popular object-oriented design principles, which helps to create flexible and maintainable code in Java and other. Identify Components and Group them in Logical LayersWhy prefer composition instead of inheritance? What trade-offs have there for jede approaching? And the converse question: when should I choose inheritance instead of composition? Stack Overflow. prefer composition over inheritance) object composition can be used to implement associations; Every OOP languages provides composition. This way, different responsibilities are nicely split into different objects owned by their parent object. For example, rdfs:subClassOf roughly corresponds to the OOP concept of a subclass. Inheritance is about changing behaviour. object composition is a way to make more complex object structures; object composition can often be a better alternative for inheritance (i. Summary. But make no mistake- inheritance of multiple interfaces is. Then I prefer to present a flattened model of this to my UI for editing, since. is-a relationships. would breathe too. Prefer composition over inheritance. แต่ในความเป็นจริง. With composition, it's easy to change behavior on the fly with Dependency Injection / Setters. Prefer composition over mixins for complex behaviors: If the desired behavior involves complex composition or multiple interacting components, consider using composition (i. "Inheritance vs 'specification' by fields. private inheritance is typically used to represent "implemented-in-terms-of". util. The newline Guide to Building Your First GraphQL Server with Node and TypeScript. I consider this to be the “ideal” way to do OCP, as you’ve enforced the “C” and provided the “O” simultaneously. This. This basically states your classes should avoid inheriting. Composition over inheritance (or composite reuse principle) in object-oriented programming (OOP) is the principle that classes should favor polymorphic behavior and code reuse by their composition (by containing instances of other classes that implement the desired functionality) over inheritance from a base or parent class. Your first way using the inheritance makes sense. Composition: “has a. You still get code reuse and polymorphism through it. I assert that the advice to prefer composition over inheritance is just fear mongering, pushed by those who failed to understand either where inheritance is best used, or how to properly refactor logic. Though, 1st we need to consider the purpose of inheritance – acquiring common characteristics and behavior, this is useful for building a hierarchy (mentioned interface-like classes also), trees. Despite these downsides, I intend to show you that inheritance is not something to be avoided like the plague. Bridge Design Pattern in Java Example. "Composition over inheritance" does not mean "replace inheritance with composition". Inheritance is tightly coupled whereas composition is loosely coupled. If you're not changing behaviour, you have no need for a subclass. Reply. You are able to switch moving. Why to prefer object composition over inheritance. If you don't require components to be added/removed dynamically to/from your entities, inheritance can be used to define entities (in languages with multiple inheritance). e. I have yet to find any major downsides to this approach, works just as I would want multiple inheritance to do. Both of them promote code reuse through different approaches. Default methods do not change this. Inheritance: “is a. " Composition is to favour over inheritance " is a guidance: When starting with OOP, it's tempting to see inheritance everywhere. how to crack software developer interview in style; A practical example for c# extension methods; How inmemory cache was getting inadvertently affected; Cross check on FirstOrDefault extension method; A cue to design your interfaces; Why you shoudn't ignore code compile warnings; A best practice to. Composition is used when there is a has-a relationship between your class and the other class. The Second Approach aka Composition. The "is-a" description is typically how an inheritance relationship is identified. Of the three OOP principles, inheritance was probably the second principle that you came to understand after encapsulation. Stack, which currently extends java. Inheritance is an "is-a" relationship. Is initially simple and convenient. Composition vs Inheritance. Eugene. #### Objectives + Subclassing & inheritance: superclass inheritance is the source of several problems that we'll examine in this reading. Hence the flexibility. In general, you should prefer composition over inheritance. util. Programmers should favor composition over inheritance in OO languages, period. A good example where composition would've been a lot better than inheritance is java. The fact that the individual checkers inherit/implement an abstract base class isn't a problem, because you can't compose an interface. Should We Really Prefer Composition Over Inheritance? In short? Yes — but not in the way I used to think. So the goose is more or less. Pros: Allows polymorphic behavior. – michex. An alternative is to use “composition”, to have a single class. Composition makes your code far more extensible and readable than inheritance ever would. Lets take a look at one of the "classical" diagrams for proxy pattern (from wiki ): I would argue that "If proxy class should implement all of the methods of original class" statement is not true - the proxy class should implement all of the "contract" methods ( Subject interface) and it hides the implementation detail i. With classic (Java, C#, and C++ to some extent) OOP, one can model shared behavior and data between classes by making those classes inherit from some common (absctract) base class with the appropriate methods and data. Publish abstraction interface in a separate inheritance hierarchy, and put the implementation in its own inheritance hierarchy. e. Challenge 2: Composition Over Inheritance. Item18: 復合優先於繼承. prefer composition over inheritance ,and so on known articles about the abuse of inheritance. Favor object composition over class inheritance. a = 5; // one more name has_those_data_fields_inherited inh; inh. This idea of keeping internal/private state is nice and you’ll probably miss it if you entirely get. Designed to accommodate change without rewriting. This chapter introduces the 'prefer composition over inheritance' design principle, by explaining the 'Strategy-Pattern'. Pros: Maps well to non-oop scenarios like relational tables, structured programing, etc "prefer composition over inheritance" is not a braindead rule saying one should avoid inheritance under all circumstances - that would miss the point of that recommendation, and would be nothing but a form of cargo-cult programming. This principle is a reaction to the excessive use of inheritance when Object Oriented design became popular and inheritance of 4 or more levels deep were used and without a proper, strong, "is-a" relationship between the levels. This comprehensive article navigates the complex discussion of composition vs inheritance in the context of ReactJS programming. Composition is flexible. The answer to that was yes. Each design pattern will assemble simple classes, unburdened by inheritance, into an elegant runtime solution. The common explanations of when to use inheritance and composition talk about “has a” and “is a” relationships: "If you have an. In the same way, inheritance can be more flexible or easier to maintain than a pure composition architecture. George Gaskin. When people say to prefer composition over inheritance they're not saying you shouldn't use interfaces in languages that have them. Sharing common behavior is one of the most important things in programming. My question is about your experience on a common problem about code readability in complex domain problems like calculation that inheritance can decrease readability. We need to include the composed object and use it in every single class. Prefer composition over inheritance; To start with, what we can be sure of is that our application needs to collect payment - both at present and in the future. NET), introducing one inheritance hierarchy automatically excludes you from all other, alternative inheritance hierarchies. E. As such it's a MUCH worse role than the simple "has a versus is a" separation. It does not matter if you are using inheritance or composition, you still need to know about the performance hit to design around it. And dealing with high inheritance trees is complexity. This isn't something you can follow without thinking about it. Favoring Composition Over Inheritance In Java With Examples. A seminal book. dev for the new React docs. The First Approach aka Inheritance. A Decorator pattern can be used to attach additional responsibilities to an object either statically or dynamically. And in Ruby people constantly forget that modules == multiple inheritance -_solnic_. So let’s define the below interfaces: When I first learned object-oriented programming, I saw inheritance as a useful way for objects to share functionality. There are several other questions like that out there, most of which got negative votes. This advice tends to apply to game logic structures, when the way in which you can assemble complex things (at runtime) can lead to a lot of different combinations; that's when we prefer composition. composition over inheritance; Random bits. The popular advice is not "stick to composition" it's "prefer composition over inheritance". You can use an. Classes should achieve polymorphic behavior and code reuse by their composition rather than inheritance from a base or parent class. Composition over inheritance (or composite reuse principle) in object-oriented programming (OOP) is the principle that classes should favor polymorphic behavior and code reuse by their composition (by containing instances of other classes that implement the desired functionality) over inheritance from a. Another one is the Composition over Inheritance Principle, which states that you should prefer composition over inheritance when possible, as it gives you more flexibility and modularity. Share. Prefer composition over inheritance; Share. E. Because of props. In composition, life of the backend class is independent and we can change back end object dynamically. Composition Over Inheritance. Trying to hide the blank look on my face, I did my best to deliver the most convincing answer I. “Favor composition over inheritance” is a design principle that suggests it’s better to compose objects to achieve polymorphic behavior and code reuse rather than inheriting from a base class. Mỗi cách thiết kế đều có ưu nhược điểm riêng, chúng ta cần xác định rõ mục đich, và. However, this. Oct 20, 2021 at 19:20 | Show 4 more comments. If you want the object to use all the behavior of the base class unless explicitly overridden, then inheritance is the simplest, least verbose, most straightforward way to express it. This is a bit of a muse day. Composition over Inheritance means that when you want to re-use or extend functionality of an existing class, often it's more appropriate to create another class that will 'wrap' the existing class and use it's implementation internally. That extends even to further subclasses - and with Java's single-inheritance model, if we have two new bits of. This being said, and to satisfy your curiosity about inheritance: inheritance is a very special relationship that should mean is-a: a Dog is-an Animal, so it may inherit from it. If you're working in a language without multiple inheritance, you should always favour composition over inheritance. Compasition is when a class has an instance of another class. Person class is related to Car class by compositon because it holds an instance of Car class. React has a powerful composition model, and we recommend using composition instead of inheritance to reuse code between components. So through this simple example, we see how the composition is favored over inheritance to maintain compatibility and where there is a possibility that the functionality might change in the future. 2. a single responsibility) and low coupling with other objects. I usually prefer using Composition over Inheritance, if i do NOT to use all the methods of a class or those methods dont apply to my class. IMHO "prefer composition over inheritance" is such a misunderstood thing it's become a dogma. 8. If we look into bridge design pattern with example, it will be easy to understand. 5. In object oriented programming, we know about 4 well-known concept of object oriented programming as abstraction, encapsulation, inheritance, and. At second, it has less implementation limitations like multi-class inheritance, etc. This is what you need. Given that the SOLID principles offer more maintainability and extensibility to your project, I'd prefer interfaces over inheritance. Also, if you need to add "additional functionality" to your interface, best option is to create a new interface altogether, following the I in SOLID, which is Interface Seggregation Principle. So in this case, good practice is using inheritance and it allows also to respect the DRY principle. In Java, this means that we should more often define interfaces and. On the other hand, there is the principle of "prefer composition over inheritance". I think above quote easily explains what I. Data models generally follow OOP more closely. Inheritance doesn’t have this luxury. Every single open source GUI toolkit however uses inheritance for the drawn widgets (windows, labels, frames, buttons, etc). Your abstract class is designed for inheritance : it is abstract and has an abstract method. This basically states your classes should avoid inheriting.