As a Java engineer in the web development industry for several years now, having heard multiple times that X is good because of SOLID principles or Y is bad because it breaks SOLID principles, and having to memorize the “good” ways to do everything before an interview etc, I find it harder and harder to do when I really start to dive into the real reason I’m doing something in a particular way.
One example is creating an interface for every goddamn class I make because of “loose coupling” when in reality none of these classes are ever going to have an alternative implementation.
Also the more I get into languages like Rust, the more these doubts are increasing and leading me to believe that most of it is just dogma that has gone far beyond its initial motivations and goals and is now just a mindless OOP circlejerk.
There are definitely occasions when these principles do make sense, especially in an OOP environment, and they can also make some design patterns really satisfying and easy.
What are your opinions on this?
If it makes the code easier to maintain it’s good. If it doesn’t make the code easier to maintain it is bad.
Making interfaces for everything, or making getters and setters for everything, just in case you change something in the future makes the code harder to maintain.
This might make sense for a library, but it doesn’t make sense for application code that you can refactor at will. Even if you do have to change something and it means a refactor that touches a lot, it’ll still be a lot less work than bloating the entire codebase with needless indirections every day.
I remember the recommendation to use a typedef (or #define 😱) for integers, like INT32.
If you like recompile it on a weird CPU or something I guess. What a stupid idea. At least where I worked it was dumb, if someone knows any benefits I’d gladly hear it!
We had it because we needed to compile for Windows and Linux on both 32 and 64 bit processors. So we defined all our Int32, Int64, uint32, uint64 and so on. There were a bunch of these definitions within the core header file with #ifndef and such.
But you can use 64 bits int on a 32 bits linux, and vice versa. I never understood the benefits from tagging the stuff. You gotta go so far back in time where an int isn’t compiled to a 32 bit signed int too. There were also already long long and size_t… why make new ones?
Readability maybe?
Very often you need to choose a type based on the data it needs to hold. If you know you’ll need to store numbers of a certain size, use an integer type that can actually hold it, don’t make it dependent on a platform definition. Always using
intcan lead to really insidious bugs where a function may work on one platform and not on another due to overfloeShow me one.
I mean I have worked on 16bits platforms, but nobody would use that code straight out of the box on some other incompatible platform, it doesn’t even make sense.
Basically anything low level. When you need a byte, you also don’t use a
int, you use auint8_t(reminder thatcharis actually not defined to be signed or unsigned, “Plain char may be signed or unsigned; this depends on the compiler, the machine in use, and its operating system”). Any time you need to interact with another system, like hardware or networking, it is incredibly important to know how many bits the other side uses to avoid mismatching.For purely the size of an
int, the most famous example is the Ariane 5 Spaceship Launch, there an integer overflow crashed the space ship. OWASP (the Open Worldwide Application Security Project) lists integer overflows as a security concern, though not ranked very highly, since it only causes problems when combined with buffer accesses (using user input with some arithmetic operation that may overflow into unexpected ranges).And the byte wasn’t obliged to have 8 bits.
Nice example, but I’d say it’skind of niche 😁 makes me remember the underflow in a video game, making the most peaceful npc becoming a warmongering lunatic. But that would not have been helped because of defines.
It was a while ago indeed, and readability does play a big role. Also, it becomes easier to just type it out. Of course auto complete helps, but it’s just easier.
If you’re directly interacting with any sort of binary protocol, i.e. file formats, network protocols etc., you definitely want your variable types to be unambiguous. For future-proofing, yes, but also because because I don’t want to go confirm whether I remember correctly that
longis the same size asint.There’s also clarity of meaning;
unsigned long longis a noisy monstrosity,uint64_tconveys what it is much more cleanly.charis great if it’s representing text characters, but if you have a byte array of binary data, using a type alias helps convey that.And then there are type aliases that are useful because they have different sizes on different platforms like
size_t.I’d say that generally speaking, if it’s not an
intor achar, that probably means the exact size of the type is important, in which case it makes sense to convey that using a type alias. It conveys your intentions more clearly and tersely (in a good way), it makes your code more robust when compiled for different platforms, and it’s not actually more work; that extrayou may need to add pays for itself pretty quickly.So we should not have #defines in the way, right?
Like INT32, instead of “int”. I mean if you don’t know the size you probably won’t do network protocols or reading binary stuff anyways.
uint64_t is good IMO, a bit long (why the _t?) maybe, but it’s not one of the atrocities I’m talking about where every project had its own defines.
“int” can be different widths on different platforms. If all the compilers you must compile with have standard definitions for specific widths then great use em. That hasn’t always been the case, in which case you must roll your own. I’m sure some projects did it where it was unneeded, but when you have to do it you have to do it
So show me two compatible systems where the int has different sizes.
This is folklore IMO, or incompatible anyways.
Incompatible? It is for cross platform code. Wtf are you even talking about
Really well said!
Getters and setters are superfluous in most cases, because you do not actually want to hide complexity from your users.
To use the usual trivial example : if you change your circle’s circumference from a property to a function, I need to know ! You just replaced a memory access with some arithmetic ; depending in my behaviour as a user this could be either great or really bad for my performance.
Exactly this. And to know what code is easy to maintain you have to see how couple of projects evolve over time. Your perspective on this changes as you gain experience.
Yes OOP and all the patterns are more than often bullshit. Java is especially well known for that. “Enterprise Java” is a well known meme.
The patterns and principles aren’t useless. It’s just that in practice most of the time they’re used as hammers even when there’s no nail in sight.
What, you don’t like
AbstractSingletonBeanFactorys?I prefer AbstractSingletonBeanFactoryManagerInterface
Can I bring my own AbstractSingletonBeanFactoryManager? Perhaps through some at runtime dependency injection? Is there a RuntimePluginDiscoveryAndInjectorInterface I can implement for my AbstractSingletonBeanFactoryManager?
I see your
AbstractSingletonBeanFactoryManagerand raise youAbstractSingletonBeanFactoryManagerDynamicImpl
As an amateur with some experience in the functional style of programming, anything that does SOLID seems so unreadable to me. Everything is scattered, and it just doesn’t feel natural. I feel like you need to know how things are named, and what the whole thing looks like before anything makes any sense. I thought SOLID is supposed to make code more local. But at least to my eyes, it makes everything a tangled mess.
Especially in Java, it relies extremely heavy on the IDE, to make sense to me.
If you’re minimalist, like me, and prefer text editor to be seperate from linter, compiler, linker, it’s not pheasable. Because everything is so verbose, spread out, coupled based on convention.
So when I do work in Java, I reluctantly bring out Eclipse. It just doesn’t make any sense without.
Yeah, same. I like to code in Neovim, and OOP just doesn’t make any sense in there. Fortunately, I don’t have to code in Java often. I had to install Android Studio just because I needed to make a small bugfix in an app, it was so annoying. The fix itself was easy, but I had to spend around an hour trying to figure out where the relevant code exactly is.
I think the general path to enlightenment looks like this (in order of experience):
- Learn about patterns and try to apply all of them all the time
- Don’t use any patterns ever, and just go with a “lightweight architecture”
- Realize that both extremes are wrong, and focus on finding appropriate middle ground in each situation using your past experiences (aka, be an engineer rather than a code monkey)
Eventually, you’ll end up “rediscovering” some parts of SOLID on your own, applying them appropriately, and not even realize it.
Generally, the larger the code base and/or team (which are usually correlated), the more that strict patterns and “best practices” can have a positive impact. Sometimes you need them because those patterns help wrangle complexity, other times it’s because they help limit the amount of damage incompetent teammates can do.
But regardless, I want to point something out:
the more these doubts are increasing and leading me to believe that most of it is just dogma that has gone far beyond its initial motivations and goals and is now just a mindless OOP circlejerk.
This attitude is a problem. It’s an attitude of ignorance, and it’s an easy hole to fall into, but difficult to get out of. Nobody is “circlejerking OOP”. You’re making up a strawman to disregard something you failed at (eg successful application of SOLID principles). Instead, perform some introspection and try to analyze why you didn’t like it without emotional language. Imagine you’re writing a postmortem for an audience of colleagues.
I’m not saying to use SOLID principles, but drop that attitude. You don’t want to end up like those annoying guys who discovered their first native programming language, followed a Vulkan tutorial, and now act like they’re on the forefront of human endeavor because they imported a GLTF model into their “game engine” using assimp…
A better attitude will make you a better engineer in the long run :)
I dunno, I’ve definitely rolled into “factory factory” codebases that are abstraction astronauts just going to town over classes that only have one real implementation over a decade and seen how far the cargo culting can go.
It’s the old saying “give a developer a tool, they’ll find a way to use it.” Having a distataste for mindless dogmatic application of patterns is healthy for a dev in my mind.
You’ve described my journey to a tea. You eventually find your middle ground which is sadly not universal and thus, we shall ever fight the stack overflow wars.
I get your points and agree, though my “attitude” is mostly a response to a similar amount of attitude deployed by the likes of developers who swear by one principle to the death and when you doubt an extreme usage of these principles they come at you by throwing acronyms instead of providing any logical arguments as to why you should always create an interface for everything
The main thing you are missing is that “loose coupling” does not mean “create an interface”. You can have all concrete classes and loose coupling or all classes with interfaces and strong coupling. Coupling is not about your choice of implementation, but about which part does what.
If an interface simplifies your code, then use interfaces, if it doesn’t, don’t. The dogma of “use an interface everywhere” comes from people who saw good developers use interfaces to reduce coupling, while not understanding the context in which it was used, and then just thought “hey so interfaces reduce coupling I guess? Let’s mandate using it everywhere!”, which results in using interfaces where they aren’t needed, while not actually reducing coupling necessarily.
I think a large part of interfaces everywhere comes from unit testing and class composition. I had to create an interface for a Time class because I needed to test for cases around midnight. It would be nice if testing frameworks allowed you to mock concrete classes (maybe you can? I haven’t looked into it honestly) it could reduce the number of unnecessary interfaces.
You’ve been able to mock concrete classes in Java for like a decade or so, probably longer. As long as I can remember at least. Using Mockito it’s super easy.
This was definitely true in the Java world when mocking frameworks only allowed you to mock interfaces.
As a dev working on a large project using gradle, a lot of the time interfaces are useful as a means to avoid circular dependencies while breaking things up into modules. It can also really boost build times if modules don’t have to depend on concrete impls, which can kill the parallelization of the build. But I don’t create interfaces for literally everything, only if a type is likely going to be used across module boundaries. Which is a roundabout way of saying they reduce coupling, but just noting it as a practical example of the utility you gain.
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One example is creating an interface for every goddamn class I make because of “loose coupling” when in reality none of these classes are ever going to have an alternative implementation.
Sounds like you’ve learned the answer!
Virtual all programming principles like that should never be applied blindly in all situations. You basically need to develop taste through experience… and caring about code quality (lots of people have experience but don’t give a shit what they’re excreting).
Stuff like DRY and SOLID are guidelines not rules.
The SOLID principles are just that principles, not rules.
As someone else said, you should always write your code to be maintainable first and foremost, and extra code is extra maintenance work, so should only really be done when necessary. Don’t write an abstract interface unless multiple things actually need to implement it, and don’t refactor common logic until you’ve repeated it ~3 times.
The DRY principle is probably the most overused one because engineers default to thinking that less code = less work and it’s a fun logic puzzle to figure out common logic and abstract it, but the reality is that many of these abstractions in reality create more coupling and make your code less readable. Dan Abramov (creator of React) has a really good presentation on it that’s worth watching in its entirety.
But I will say that sometimes these irritations are truly just language issues at the end of the day. Java was written in an era where the object oriented paradigm was king, whereas these days functional programming is often described as what OO programming looks like if you actually follow all the SOLID principles and Java still isn’t a first class functional language and probably never will be because it has to maintain backwards compatibility. This is partly why more modern Java compatible languages like Kotlin were created.
A language like C# on the other hand is more flexible since it’s designed to be cross paradigm and support first class functions and objects, and a language like JavaScript is so flexible that it has evolved and changed to suit whatever is needed of it.
Flexibility comes with a bit of a cost, but I think a lot of corporate engineers are over fearful of new things and change and don’t properly value the hidden costs of rigidity. To give it a structural engineering analogy: a rigid tree will snap in the wind, a flexible tree will bend.
Whoever is demanding every class be an implementation of an interface started thier career in C#, guaranteed.
Java started that shit before C# existed.
I’m my professional experience working with both, Java shops don’t blindly enforce this, but c# shops tend to.
Striving for loosely coupled classes is objectively a good thing. Using dogmatic enforcement of interfaces even for single implementors is a sledgehammer to pound a finishing nail.
The main lie about these principles is that they would lead to less maintenance work.
But go ahead and change your database model. Add a field. Then add support for it to your program’s code base. Let’s see how many parts you need to change of your well-architected enterprise-grade software solution.
Sure, it might be a lot of places, it might not(well designed microservice arch says hi.)
What proper OOP design does is to make the changes required to be predictable and easily documented. Which in turn can make a many step process faster.
I have a hard time believing that microservices can possibly be a well designed architecture.
We take a hard problem like architecture and communication and add to it networking, latency, potential calling protocol inconsistency, encoding and decoding (with more potential inconsistency), race conditions, nondeterminacy and more.
And what do I get in return? json everywhere? Subteams that don’t feel the need to talk to each other? No one ever thinks about architecture ever again?
I don’t see the appeal.
I guess it’s possible I’ve been doing OOP wrong for the past 30 years, knowing someone like you has experienced code bases that uphold that promise.
We all have or own experiences.
Mine is that it helps in organization, which makes changes easier.
YAGNI ("you aren’t/ain’t gonna need it) is my response to making an interface for every single class. If and when we need one, we can extract an interface out. An exception to this is if I’m writing code that another team will use (as opposed to a web API) but like 99% of code I write only my team ever uses and doesn’t have any down stream dependencies.
The principles are perfectly fine. It’s the mindless following of them that’s the problem.
Your take is the same take I see with every new generation of software engineers discovering that things like principles, patterns and ideas have nuance to them. Who when they see someone applying a particular pattern without nuance think that is what the pattern means.
And then you have clean code. Clean code is like cooking with California Reapers. Some people swear on it and a tiny bit of Clean Code in your code base has never hurt anyone. But use it as much as the book recommends and I’m gonna vomit all day long.
My opinion is that you are right. I switched to C from an OOP and C# background, and it has made me a happier person.
Also the more I get into languages like Rust, the more these doubts are increasing and leading me to believe that most of it is just dogma that has gone far beyond its initial motivations and goals and is now just a mindless OOP circlejerk.
There are definitely occasions when these principles do make sense, especially in an OOP environment, and they can also make some design patterns really satisfying and easy.
Congratulations. This is where you wind up, long after learning the basics and start interacting with lots of code in the wild. You are not alone.
Implementing things with pragmatism, when it comes to conventions and design patterns, is how it’s really done.
I’m making a separate comment for this, but people saying “Liskov substitution principle” instead of “Behavioral subtyping” generally seem more interested in finding a set of rules to follow rather than exploring what makes those rules useful. (Context, the L in solid is “Liskov substitution principle.”) Barbra Liskov herself has said that the proper name for it would be behavioral subtyping.
In an interview in 2016, Liskov herself explains that what she presented in her keynote address was an “informal rule”, that Jeannette Wing later proposed that they “try to figure out precisely what this means”, which led to their joint publication [A behavioral notion of subtyping], and indeed that “technically, it’s called behavioral subtyping”.[5] During the interview, she does not use substitution terminology to discuss the concepts.
You can watch the video interview here. It’s less than five minutes. https://youtu.be/-Z-17h3jG0A
SOLID is generally speaking a good idea. In practice, you have to know when to apply it.
it sounds like your main beef in Java is the need to create interfaces for every class. This is almost certainly over-engineering it, especially if you are not using dependency inversion. IMHO, that is the main point of SOLID. For the most part your inversions need interfaces, and that allows you create simple, performant unit tests.
You also mention OOP - It has it’s place, but I would also suggest you look at functional programming, too. IMHO, OOP should be used sparingly as it creates it’s own form of coupling - especially if you use “Base” classes to share functionality. Such classes should usually be approached using Composition. Put this another way, in a mature project, if you have to add a feature and cannot do this without reusing a large portion of the existing code without modifications you have a code-smell.
To give you an example, I joined a company about a year ago that coded they way you are describing. Since I joined, we’ve been able to move towards a more functional approach. Our code is now significantly smaller, has gone from about 2% to 60% unit testable and our velocity is way faster. I’d also suggest that for most companies, this is what they want not what they currently have. There are far too many legacy projects out there.
So, yes - I very much agree with SOLID but like anything it’s a guideline. My suggestion is learn how to refactor towards more functional patterns.
In my experience, when applying functional programming to a language like java, one winds up creating more interfaces and their necessary boilerplate - not less.
True… I personally dislike Java and work mostly in Kotlin these days.
99% of code is too complicated for what it does because of principles like SOLID, and because of OOP.
Algorithms can be complex, but the way a system is put together should never be complicated. Computers are incredibly stupid, and will always perform better on linear code that batches similar operations together, which is not so coincidentally also what we understand best.
Our main issue in this industry is not premature optimisation anymore, but premature and excessive abstraction.
This is crazy misattribution.
99% of code is too complicated because of inexperienced programmers making it too complicated. Not because of the principles that they mislabel and misunderstood.
Just because I forcefully and incorrectly apply a particular pattern to a problem it is not suited to solve for doesn’t mean the pattern is the problem. In this case, I, the developer, am the problem.
Everything has nuance and you should only use in your project the things that make sense for the problems you face.
Crowbaring a solution to a problem a project isn’t dealing with into that project is going to lead to pain
why this isn’t a predictable outcome baffles me. And why attribution for the problem goes to the pattern that was misapplied baffles me even further.
No. These principles are supposedly designed to help those inexperienced programmers, but in my experience, they tend to do the opposite.
The rules are too complicated, and of dubious usefulness at best. Inexperienced programmers really need to be taught to keep things radically simple, and I don’t mean “single responsibility” or “short functions”.
I mean “stop trying to be clever”.








