Why not Java

davidsackstein profile image david-sackstein ・3 min read

Holy Wars in our profession are all too common. Proponents of different ecosystems find it hard to agree on which method, discipline, language, operating systems and toolsets are superior.

Our judgement of ecosystems with which we are not familiar is heavily influenced by prior knowledge and experience. In order to appreciate the strengths of what we do not use, it is often not enough to learn more about them, but also to accept different perspectives and approaches and to judge those systems from these different perspectives.

I realized this many years ago when learning TDD.

At first, TDD seemed preposterous, unreasonable and impractical approach to developing software, but today I use it readily whenever I get the chance.

Learn the technicalities of TDD took no time at all, but that was not enough for me to see its strengths. What made the difference for me was a deeper understanding of the importance of requirements analysis and of testing and refactoring in the development process. Once those were understood, TDD quite naturally became the sharpest tool in the box.

I had a similar experience when I finally sat down to study Functional Programming. Unlike TDD, there is a lot to learn in FP. But FP only became an important tool for me when I finally grasped the concepts of immutability and functions, the importance of function honesty and the play between Functional Programming and Object Oriented Programming. In order to use Functional Programming effectively, you need to approach a problem differently. When you do, the Functional Programming tools will help you solve it.

I open with this idea in order to convince you that I sincerely prepared myself for such an epiphany when I embarked on my journey with Java about one year ago.

I have many years of experience using .Net (C#).

In those years I have learned to admire the power of the entire ecosystem: the languages, libraries, tooling and maturity. I have found that it allows me to concentrate on the job at hand and helps me write high quality software quickly. .Net also keeps up to date with the latest trends, adding new functionality without increasing the complexity of existing code, allowing me to learn about the latest engineering practices from the ecosystem itself.

.Net is truly a masterpiece of engineering.

I am also no stranger to Java. But until a year ago, I had not used Java for any commercial project. For years, I have been observing the Holy War between the .Net and Java communities from the sidelines.

The Java community claims that its ecosystem, which is much more widely used than .Net, is at least as powerful as that of .Net. Java has the additional advantage of being OS independent and is supported by a larger and active open source community.

I have always had my doubts though. From what I had seen of the language, it had far fewer features than C# and the ecosystem seemed over-complex for my liking.

But now I have no doubts. A year after my journey started, I can say that the epiphany never occurred, and for me the dilemma is over.

The Java language is weak. The ecosystem, in particular that of Spring Boot, is fragile and difficult to maintain. There are too many ways to do one thing and very often, only one (if any) works, leaving the developer to repeatedly apply trial and error in a desperate search for a solution.

In the link at the bottom of the post I explain what brought me to these conclusions.

But one further note is worth mention.

I approached my study of Java with an open mind. At every choice and junction I consulted with experts, studied online courses and read posts online. I tried to make all my decisions align with the Java approach, and not with my habits from .Net.

I came to Rome to learn from the Romans.

Enjoy reading more at this link:


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Hi David, you are bringing in good points.

I am, like you, a long-time .NET developer. And long ago, when there was a religious war between Java and .NET, there weren't many ecosystems like we have today. JavaScript was not that strong, Python was not as much used as today, functional programming was only used academic, and so on. And, .NET was not always open-source, not multi-platform, and the community was not so strong as it is today. That said, most of the design principles that we use today in Object-Oriented programming, came from the Java community. Most of the great Object-Oriented names we know today came from there.

I am sure that there are still a lot of knowledgeable people doing great software using Java, and there is also a lot of legacy code in Java out there. I believe that they brought a lot of knowledge and experience to the table, that the .NET team and community was able to benefit from. Microsoft was very smart to take the good bits and, for me, the decline of Java became when Sun was acquired by Oracle.

Choosing one over the other, most of the time is a business decision that depends on the software/tools and expertise that you already have inhouse. You might not want to start a new .NET team that is not able or will not be happy to maintain your huge legacy Java code. And I see nothing wrong starting a new software using Java if you know what you are doing and will be happy with it.

I am not confronting your opinion, just expressing my own.


Hi Vinicius Rocha,
You raise good points. I think that Java created a revolution in the 90's and introduced many important ideas that we still benefit from today. And indeed, I think Microsoft leveraged that knowledge to build an even better system.
In fact, the only difference of opinion we have is what the considerations for choosing Java over .Net for new projects might be.
You say that it is a fair decision if you know what you are doing. Unfortunately I think that this is not enough, because you need to know too much to make your development as smooth as with .Net.
I would say that it is a fair decision to choose Java over .Net for a new project if you know what you are losing :)


"if you know what you are losing" I like that! :)


2) Java has introduced Streams (similar to LINQ in C#) to make it easy to manipulate iterables in a functional, declarative way.
But an Array in Java is not an Iterable (and neither is a HashMap).
Java 8 enables you to convert it to an Iterable by implementing a functional interface and Guava is a third part library that does that for you but it is not part of the language. This probably has a performance impact, but it also makes the work of collecting streams and converting them to arrays just that much more difficult to do.

For me - you misunderstood like everything. I could debunk what you wrote, but, forgive me, my time is limited and I have better things to do.
In this little block of text you put so many misconceptions and false assumptions - I don't even know where to start.
Regarding streams, they are much more than LINQ-analogue. For starters, they are an interface that can (should be and is!) implemented by 3rd party vendors. That's awesome. You can issue i.e. SQL query with streams without touching sql. In my work I use streams to build queries carried over by TCP, and the querying command is built upon the streams.
From this point - one must address your claim that "java is weak". Oh gosh, I imagine you rising similar claim against C/C++... This claim has similar level of truthfulness. Not covering 100% scenarios is nothing against the language itself. It's not even a thing for the language, but for its standard library. Yet, again, I'll repeat, you could rise the same argument against C, python, ruby, anything. Well, perhaps, except c# running on dot net bloat. But wait, how many TDD frameworks are there? ORMs? Window building toolkits? I stopped using when Silverlight was cool. What happened with it?

Arrays? Being iterable? What for? If you want to have iterable backed by rawxarray, use ArrayList. Iteration over HashMap? First question: in what order? This collection is designed to store data with quick random access for a given key, not for iteration.
You mentioned Guava, said it's not part of "language", again proving you don't understand what you write about. When we talk about something, we should share the common dictionary. Language doesn't include libraries. Java as language specifies what are the opcodes, not the classes, they belong to the standard library, which is JDK. No library is part of the "language". By definition. It can be part of the standard library, in regards to java - the JDK, nevertheless belonging to jdk or not it doesn't affect the performance. And if we are talking about Guava, not knowing it makes you crippled. They provide some great and performant libraries, like for example, the ConcurrentHashMap.

You'd feel in similar way if I wrote that C# has no good logging tools because Console.out is difficult to use for a long term. That's BS.

Please, learn how to use something before you critique that thing.


@mt30 as I am not a Java expert I may have made a few mistakes in terminology.
But I do not think that your comments address the essential issues I raised.
If you like, we could select one point and discuss it in more depth.
I am open to retract my conclusions and others might benefit from the discussion too - but you say you do not have time for that.


Misunderstanding difference between standard library and language itself is beyond your issues with java.

I opened your post to learn some actual issues with java. I don't know, something about cold start, about size of "fat jars", about where java lies behind scala/kotlin/rust/erlang/lisp. Something about abuse of reflection, agents, ineffective practices of defensive programming, performance impact of Optional<> ... Instead you wrote that using guava might affect performance because it's not part of jdk... It's trivial to benchmark this. But checking it requires acting professional, being objective. Using such half baked claim against whole language is just unprofessional. Taking on the point that packages are useless, and final argument was that IntelliJ generates import statements for you - that's laughable. I don't even how to address this, where to start with explaining why you are wrong, except for treating you as a total beginner. I don't even know where to start and I feel helpless, that's where the laugh comes from. This is what made me feel offended.
In my understanding, you are disappointed that java is not c# (assumption: backed by dot net package appropriate for 2019) with it's main (?!) IDE not being copy of Visual Studio.
Not to mention, that NetBeans or Eclipse have more right to be called the main IDE for java, Eclipse for being older, NetBeans for being provided by Sun/Oracle.
Do you even know that for years the best refactoring toolkit for VS was made by JetBrains? The guys behind IntelliJ?
You wrote pretty huge document about where java falls short, but for the part I read - you focus on parts where you don't know how to use it, dont understand what you do, and regret that it's not c#. Understand my disappointment. I expected much more, given the fact you published the document on separate URL, as a word document, and you publish it using your real name. On the contrary I'm just an anon around the internet and can change the nickname whenever I want.

On the other hand I can add fair share of criticisms for c#, like I don't get why I can incre the performance by order of magnitude by marking blocks of code as unsafe, unrolling the loops and inlining getters/setters. Has Microsoft done something with that since 2014 when was the last time I done something with that ecosystem?

Don't get me wrong, if you take another approach to the subject, I'd be glad to read your article and respond to it.

I find that anonymous writers are more likely to make personal comments and use offensive language.
As we are not making any progress I think we should just agree to disagree and end it here.
Don't get me wrong, if you take another approach to the subject I'd be glad to have this discussion with you.

To start making progress, acknowledge what I wrote, because I put few (or even a dozen) screens of text which you completely ignored, dismissed by calling it personal and offensive. Refer to what I wrote, not to your feelings. To illustrate up your zero level of attention on what I wrote, you can't write my nickname properly. :(

I acknowledge you made some good points - which I can refute.
But you also used the terms laughable, "total beginner", "unprofessional", "half baked claims" and the like.
So let's just agree to disagree.


Btw, Java doesn't end on Spring. It doesn't belong to the JDK (for sake thing you rejected Guava), there are lots of other DI frameworks in java.

Not to mention, in the java community, Spring has its share of criticisms for abuse of annotations and performance impact it creates.


Please don't be cynical. TDD does not replace design, refactoring is always needed and this post is not about TDD.


2) Package visibility boundaries are only as strong as class level visibility.

And this claim is either a bold lie or proof that you don't know what your writing about. As with pre- as with post-java9 restrictions.

In some point you wrote about packages as encapsulation, showing lack of knowledge of class loaders.

Yet, the masterpiece argument against JAVA is here:

3) Package imports are effectively not explicit (...)
But in Intellij you never actually write your own import statement.



I don't think laughing (as in ROTFL) is very productive criticism.
You seem to be offended by my judgement of Java, and none was intended.
There is something more you should be aware of.
One of my main criticisms of the ecosystem is that you need to learn a lot in order to use the framework effectively. The more areas you think I need to study actually emphasize this weakness.
True, as professionals, we should learn whatever we need - in depth - as needed. But I think that .Net shines because, you need to learn relatively little to get things done.
There are much fewer surprises.
But let's not bicker about this.
If you care to spend the time to explain your points in more detail, and you are willing to listen, and possibly learn too, then let's continue this discussion.
If not, I respect your opinion, but see no need to change mine.

  1. System design is not old fashioned.
  2. TDD is not synonymous with "hack things about"

I really have no intention of discussing TDD here, but maybe you should do some reading up on the subject too.