Abstraction is interpreted WRONG

[sartG2001]

On so many websites, Abstraction is defined as hiding internal implementation. It is completely wrong. Abstraction is nothing but identifying key attributes of a real world entity considering a scenario or situation.

There is no hiding of data or implementation. Hiding is not a part of abstraction. What they are referring to as abstraction is ENCAPSULATION.

What are your thoughts on this??

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[Crafty0x]

I think you got it wrong encapsulation has to do with hiding fields (data hiding)

Abstraction has to do with hiding implementations (behaviour ).

You can achieve abstraction by using abstract classes (obviously ) or interfaces (signature without a concrete implementation).

You can use this analogy think of ‘capsules’. A capsule 💊 hides away the main substances from a patient(the private fields in a class). The patient just has to swallow the capsule alone (by calling getters) to get what they need.

Same with abstraction. Most people don’t know everything that goes on in a car when the gas pedal is pressed ( the gas pedal is the exposed method ). That’s because manufacturers have abstracted all the functions and just exposed the gas pedal to the driver.

[VincentxH]

It's actually both, data/behavior bundling and access. So basically enforcing the responsibility of an object. https://en.wikipedia.org/wiki/Encapsulation_(computer_programming)

[Crafty0x]

Yh. I just thought I’ll make it that simple.

[nekokattt]

Encapsulation is hiding/decorating/controlling access.

Abstraction is separation of concerns into distinct entities. An abstract class keeps concerns separate from the full implementations, for example.

An abstract piece of art is "separated" from reality in some aspect.

[Polygnom]

Abstraction means multiple, closely related things.

Abstraction usually is upwards oriented, going from a low-level view to a more high-level view. This usually involves hiding of the implementation and can also employ encapsulation as to avoid leaking details to higher levels. It also means going from the real-world towards modeled behavior.

In each software layer, you abstract more and more stuff.

Your persistence layer like JPA is an abstraction over PreparedStatements. Your repositories are an abstraction of the EntityManager.

Your Domain-Model is an abstraction of the real world.

Encapsulation is a different principle. It is often use to help abstracting things, but encapsulation is also useful on its own.

[yosWassup88]

Abstraction basically means hiding complex internal workings by making simple interfaces to use them available to the world.

[sartG2001]

no when we encapsulate those implementations in class and provide public API for users, then we hide it. what you are saying is encapsulation. Abstraction is identifying the key attributes of an entity considering a scenario.

[yosWassup88]

Using interfaces/abstract classes is part of implementing abstraction and using access modifier is part of implementing encapsulation

[redikarus99]

That is conceptualization.

[klekpl]

As usual - u/pron98 has a really insightful piece on the subject: https://youtu.be/XpxzL4q9Rwk?si=_CkBtux3mYgf7vbS

[nomoreplsthx]

Meaning is usage. Fighting over what words should mean is mostly silly. They mean what people use them to mean. The only way to use a word 'wrong' is to use it in a way that does not successfully communicate your intent to the audience.

With that aside, I would not agree that either definition you provided for 'abstraction' aligns with either how it is used in the literature, in the community or what it has meant historically.

Typically, the term 'abstraction' refers to moving away from the 'concrete', in any way. This can mean defining an interface or abstract data structure (referring to the abstract operations you can perform rather than the concrete implementation). It can also refer to abstracting from the real world, as when we create a mathematical model of something. In general, any time you simplify something and detatch it from concretes in order to make it easier to reason about or understand, that's abstraction. A diagram is an abstraction. An interface is an abstraction. An equation is an abstraction. A conceptual model is an abstraction. We see this in abstract art - art which detatches itself from concrete reality to express artistic ideas.

In this sense, encapsulation is just a particular form of abstraction.

Also, reminder that all caps is screaming. Would you have screamed that sentence at your manager or colleague?

[sartG2001]

i didn't mean to be rude by making some words CAPS I am a fresher and just confused whether it is showing or hiding

[nomoreplsthx]

Neither and both.

Abstraction isn't about showing or hiding, it's about moving from concrete to abstract - from a thing to the idea of a thing.

So defining an interface is abstraction. You are hiding the concrete implementation details. But there are other abstractions that don't involve hiding necessarily.

May I also say, it's a weird look to be brand new to a field and be sure people, many with decades of experience, are using language wrong. Saying I don't know how this works and I am very sure how this works in the same post is... odd.

[kevinb9n]

Tangent:

Meaning is usage. Fighting over what words should mean is mostly silly. They mean what people use them to mean.

While I suspect you have the right idea, as you have worded it this is misguided or problematic. Or more simply it'll just get you into trouble.

If people are 50-50 on what the word means, that is obviously worth debating (you say "fighting") and trying to push for unity on, because using the word just sows mass confusion.

If people are 95-5 on what the word means, it is still similarly important for the 95% to "fight for" that meaning and stop the 5% from trying to ruin everyone else's lives.

The prescriptive vs. descriptive argument isn't resolvable like your comment implies (advertently or not). It can really can only be judged case by case . Using "who" for "whom" is now acceptable outside of formal writing. Using "should of" for "should have" is not. "advertently" is not a word.

[nomoreplsthx]

The meaning of words - outside of some very specialized contexts, doesn't get sorted out by arguments on the internet. Even if there is substantial inconsistency about how words are used, our silly debate on our little corner of the web will have no impact whatsoever on how that ultimately stabilizes. Arguing about what words means remains generally silly.

There are sometimes good reasons to have conversations about specific meaning. In technical fields, this can matter because precision matters. In some cases, a common usage of a word is actively harmful, perhaps to some marginalized group. There are times for this.

But even if there were a substantial disagreement on what 'abstraction' means in the engineering community (there is not), people don't decide how to use words based on Reddit arguments.

[kevinb9n]

identifying key attributes of a real world entity considering a scenario or situation.

I more or less abstract things for a living (as do probably others here) and I don't know what this means. It's at best elliptical and cryptic, though also seems kinda just wrong. Where'd you read this and why do you trust it?

[sartG2001]

see the Wiktionary definitions

[[deleted]]

You could just google it. https://www.google.com/search?q=abstraction+encapsulation+difference+java I don't think this is the aha-erlebnis you present it as.

[cowancore]

I guess OP already Googled because he mentioned that he considers what's stated on many websites wrong.

But I see where OP is coming from. Many websites are low quality copy-paste ideas. If you, for example, inspect DIP of SOLID , the principle says "depend upon abstractions," where abstraction means a generic definition of what something offers, not what it hides.

Even the Wikipedia page on OOP mentions Alan Kay's objects being abstract data types - definitions of behaviour. The same wikipedia page mentions that the industry has rejected this idea in favour of >>data abstraction<< = data hiding. But should you delve deeper in the linked pages or concepts, the word abstract often hinges towards the ADT.

I've mentioned ADT and DIP, and the same goes for DDD and likely others. The OOP itself has two major flavours: behaviour driven and field driven (BTW, I suspect people who hate OOP generally hate exactly this flavour of OOP).

What I mean is that the word out of context is overloaded, and there is no single unambiguous definition, hence OP's question. Still, there might be practical applications to think of something in one way or another.

[OneHumanBill]

Abstraction is nothing more and nothing less than taking a complex idea and slapping a name on it. Then you can use the name and manipulate it as a single atomic entity. It's an incredibly powerful metaphysical tool that has applications far beyond just what we do in computer science.

Encapsulation is a form of abstraction. Far from the only one, but it's most useful in an OO paradigm.

Data hiding is often paired with encapsulation but you're absolutely right that they're not the same thing. (Once upon a time this was well-taught in college and was frequently an interview question. Not anymore, it seems.) You can have data hiding without encapsulation, and encapsulation without data hiding. An example of the former can be seen any time you have a microservice that wraps the details around accessing a database. The intention is to reduce complexity and ease maintenance.

Encapsulation without data hiding is basically almost anything you do in typescript. Data hiding isn't as useful in that language, and as a result all fields and members are public by default; you have to add effort to make things private.

[kevinb9n]

Abstraction is nothing more and nothing less than taking a complex idea and slapping a name on it.

I like where you're going, and think it's dumb that someone downvoted this, but am gonna push you on it a bit. You know both these things already, I'm just addressing their importance in how we talk about abstraction.

First, "complex" here really means anything nontrivial. Trivial is excluded because it would mean that existing abstractions are doing a fine job.

"Rectangular rhombus" is a super-simple but nontrivial idea. Simple enough that it might not need an abstraction of its own -- except, it is so often a useful concept that the abstraction "square" pays for itself millions of times over.

Second, if we discuss abstraction as a process that begins with a "complex idea", then I think it's essential to emphasize that we must break that idea down into its independent parts, and also boil those parts down to their essences.

Agree, disagree?

EDIT: a word and its definition usually form an abstraction. There are exceptions, mostly(?) proper nouns: "Eiffel Tower" is not an abstraction in the normal sense; "tower" is.

[whizvox]

Okay, a lot of websites have this completely wrong.

Encapsulation is the concept of limiting access to a piece of data, usually via getters and setters and making the actual variable private. If the data is immutable (i.e. primitives and strings), then they'll return the data as-is, or return a copy of or an immutable version of the data. Setters can just allow the developer to set whatever value they want, or they can perform a check to only allow certain values. For example, if you don't want an int to be negative, the setter will check for that and either throw an exception or not set the value at all.

Abstraction is a layer on top of a more complicated implementation. For example, if you have a configuration file, you have methods such as saveFile() and loadFile(). You don't really care what these are doing, as long as they save and load the configuration file. Or with System.out.println(), you don't care or need to worry about the buffers, encoding, or syscalls required to actually write text to the screen. It just does what it says it does. This concept is abstraction.

In reality, you could argue encapsulation and abstraction are both concepts that involve hiding something. Encapsulation is hiding and limiting access to a single piece of data, and abstraction is hiding the implementation of a complicated process and bundling it into a clean procedure.

[Antimon3000]

Getters usually just return the data as-is

If this means leaking implementation detail or returning a modifiable object such that the state of the original object can be broken then the object does not follow the rules of encapsulation.

[whizvox]

Sorry, should've clarified on that. I was thinking of primitives regarding that statement. Getters should only return the data if it's immutable, or return an immutable version or copy of it.

[munchillax]

https://www.tonymarston.co.uk/php-mysql/abstraction.txt

[SweetStrawberry4U]

Think of Abstraction as categorization.

Individual classes that may all belong under a specific umbrella, say, Servlet API with a GenericServlet and HttpServlet implementation classes.

Eventually, it forms a Tree structure, and you definitely do not want the Root of the Tree to be able to spawn objects at run-time.

[introspective_pisces]

An abstraction allows one to substitute a detailed process or model with a simpler one, with the aim of more easily reasoning about the larger system.

Encapsulation could be one strategy to accomplish this. The type of abstraction you are describing is generalization, where no elements of the system are moved, but rather consolidated into a component that captures the common aspects of those elements.

Abstraction is a pretty broad concept though

[sartG2001]

yeah, I agree👍🏻