The Reason For Java's Staying Power: It's Easy To Read

jfruh writes: Java made its public debut twenty years ago today, and despite a sometimes bumpy history that features its parent company being absorbed by Oracle, it's still widely used. Mark Reinhold, chief architect for the Oracle's Java platform group, offers one explanation for its continuing popularity: it's easy for humans to understand it at a glance. "It is pretty easy to read Java code and figure out what it means. There aren't a lot of obscure gotchas in the language ... Most of the cost of maintaining any body of code over time is in maintenance, not in initial creation."

Comments

Re:Stability

[DickBreath]

Not only do you have to re-learn basic elements every decade, you might have to rewrite very old code to work on current systems.

The people who make these incompatible changes vastly underestimate the cost of such incompatibilities.

The sheer amount of working Java code is not only why the language will stay around for a long time, but economically represents a very large amount of wealth.

Re:Readability is crucial for new languages

[DickBreath]

Readability goes along with 'toolability'. The fact that tools can 'understand' Java code and therefore can correctly make so many kinds of automated changes to the source code is a major sign of readability. If it is not possible to make tools that can do precise and sophisticated manipulations of the source code, then chances are that humans cannot understand it easily.

As an example of what I mean by 'toolable'. When I rename a variable in Java, every instance of that variable throughout the entire project are changed. This is not a dumb 'search and replace'. It is a precise change made by tools that use most of the Java compiler front end in order to make these changes. Similarly if I rename a method, the change is precisely made throughout the source code. It doesn't matter if there is a variable, or a class or even another method elsewhere with the same name, there can be no possible confusion. Just as the compiler has no confusion about what identifier 'foo' in some line of code refers to, the renaming and refactoring processes are equally precise. That is what is meant by toolable.

Re:Yes & the sheer amount of existing code/fra

[Anonymous Brave Guy]

I'd agree with the ecosystem being a huge factor in Java's success.

More than that, it is a relatively closed ecosystem. Tools like JNI are available, but in practice few projects seem to use them. Mostly, either you're working in JVM world or you're working somewhere else. That's a lot of momentum to overcome for any long-standing project or development team to move to another language, tool chain, standard library, and so on.

I also think the summary's claim that Java is easy for humans to understand at a glance because of its simplicity is a mischaracterisation. Java is a relatively verbose, inexpressive language, so actually it can take quite a long time to figure out how any given piece of code works. What Java does offer is that an average developer can reliably figure out how any given piece of code works, even if it takes a while. For long-running, large-scale projects that is a valuable attribute for a programming language.

Seen enterprise software?

[ThePhilips]

It is pretty easy to read Java code and figure out what it means.

Many who deal with the "enterprise" software would simply laugh at the statement.

But hey, the same argument was often made about the BASIC. And I always said that Java and BASIC users are very similar.

Re:"Easy to read" is non-sense

[LWATCDR]

I disagree that it is because java is easy to read. Java is easy to write. A good programer can write an app in Java and have it work really well. A bad programer can write an app in java it will work.
With C++ a good programer can write an app and it will work but you really have to watch for a lot of gotchas. A bad programer can not write a program that works in C++ because it will leak memory, stomp on memory, and have issues with pointers.
Java is better at stopping the little brain farts from blowing up in your face.
C++ is a lot more fun to write in IMHO.

Re:Yes & the sheer amount of existing code/fra

[Anonymous Brave Guy]

Yeap, of course repeat the type of the object twice, the ugly diamond operators, use else if instead of elif, etc, produces verbosity, but this is not related to be easy or not to understand.

The thing is, I think it is related to how easy something is to understand.

If I can express an algorithm as a single function of 10 lines then, other things being equal, that will be easier to understand than distributing the same algorithm across 5 functions each of 20 lines. You can see the whole thing at once, instead of jumping around within or between files. You don't have overheads of passing around and returning values.

Similarly, if I can express a simple bit of logic as a clean one-liner, while a verbose style requires 6 lines of manual loop/conditional logic and maybe a function wrapped around it, then I'm thinking about what that logic is doing and it how it fits in with the other logic around it while you're still worrying about loop counters.

Here's a version of finding all the items less than 10 in a list, written in Haskell, a relatively powerful language:

items = [1, 15, 27, 3, 54]
result = filter (<10) items

Here's a slightly more verbose version, written in Python, also a language known for being clean and expressive:

items = [1, 15, 27, 3, 54]
result = [item for item in items if item < 10]

And in contrast, here is the best Stack Overflow has to offer about implementing this sort of requirement in Java.

Spoiler: There are basically three kinds of replies. Some write out entire functions to implement the filter using a manual loop. Some use a third party library to do a more clumsy variation of the Python and Haskell examples above. And a few recent ones use Java 8 to do a slightly less clumsy variation of the Python and Haskell examples above. The clear trend is to try to get away from classical, verbose Java to something more powerful and expressive. Like Scala, according to the first comment on the original question...

Re:Yes & the sheer amount of existing code/fra

[AuMatar]

Totally disagree. If I see

for(int i: items) {
  if(i<10){
    results.add(i);
  }
}

I know exactly what it does. Anyone who has done any programming in any language can guess what it does. Its simple, easy to read, and if you want can be pulled into a function. Your haskell and Python implementations are unreadable and requires the user to think about each line. They're inferior to straight forward programming by orders of magnitude and should never be used.