The following notes were written very late at night in a somewhat low blood-sugar state of mind.
A quick disclaimer: I fully acknowledge that Java deserves its place as the premier platform
for enterprise programming. I am a Java fan. No really, I am. However, my DART
code is in C++,
and I've often been asked to justify this. The following rant is my somewhat defensive attempt
to explain myself. I realise that I come across as a bit of a javaphobe here, but what the hell,
I'm going to leave it up here for posterity. Or whatever. IanHolmes
, March 25 2005
Why DART is not written in Java
- First up, you better realise that language proselytising is immature.
I certainly realise it. Preaching language preference is just a waste of time.
Grown-up programmers know multiple languages and use the best tool for the job.
Nothing about my use of C++ in DART
is religious or ideological or dogmatic.
It's just practical. That said...
- There are still reasons why we pick the languages we do.
I have been asked to justify, or (more usually) scoffed at for, my choice of C++
as the programming language for DART
. Many times. Why not Java??
As if no conceivable reason could be pronounced in polite company, without making a face.
- So here are those reasons. brace yourself
Still-valid reasons why DART should not be in Java
- Java is still not as fast as C++.
Java fanatics refuse to believe this. They're in denial.
However, Java will always inherently be slower than C, partly because of the bytecode
interpretation, but also because you don't have fine-grained control over memory allocation
(which is a major cause of nonlinearity and slowdown in real applications).
Java's slowness seems especially apparent for numerically intensive computations.
See for example the great language shootout
- Java doesn't have templates
I know about generic java. But, again, it isn't "there" yet. Not widely supported,
not widely accepted. It's a great idea, but it isn't yet a standard.
As a result, java programmers end up doing dynamic casts all the time, and their
code spills runtime cast exceptions all over the place. This is just dumb, and it
adds to java's inherent slowness. A high-level language should be typesafe and statically
bound where possible. Java isn't. Generic java maybe, but again, it's not there.
- It is therefore difficult to convert a large amount of working legacy code into java from C++
but i would welcome volunteer offers.
The test I care about passing (in a JUnit sense) include XrateTests
Reasons why I'm STILL lukewarm about java as a language compared to C++
With its absence of templates, its insistence on long variable names, its ugly
and its lack of operator overloading and other
neat syntactical shortcuts, java forces programmers to type more. My fingers thank
me for using C++.
- Java still has problems with incompatibilities, stale dependencies and changing APIs
Java was meant to solve these problems. And it doesn't. OK, you get incompatibilities with
C and (especially) C++, but in my experience these are no harder than Java problems to fix,
and usually easier. Perhaps this is just what I'm used to, but given that this is one of
the things Java was supposed to not
do, I think it's pretty sad.
- Well-written C++ is just as safe/secure/stable as Java
I've never had a segfault I couldn't immediately fix by compiling in debug mode
(where I use bounds-checking wrappers around the
template, among other safety
checks). Java programmers, on the other hand, face runtime exceptions on a regular basis
that simply don't occur in good ol' typesafe C++.
- The C++ standard template library is better than Java's standard library
Sorry, it just is.
Old, no-longer relevant reasons why DART was not written in Java
- Java wasn't "there" in 1998
When I started writing DART
, java was still underdeveloped. In fact, early development
on dart began in 1996. At that stage, java was still a fun curiosity.
Of course, now java is much more established, which makes C++ code (arguably) legacy.
- Java wasn't "there" in 1995
I loved the java buzz. Seriously. I lapped up every drop of it.
And my phd supervisor (rightly) recommended I stick with a better-established
language, in order to meet scientific goals within the period of my Phd funding.
Sometimes not being an early adopter is the right choice. However, java is a pretty smart choice
right now. Why?
Reasons why it would be good for DART to be written in Java
OK, finally I have to say this by affirming that I'm STILL a java fan
and I recognise that DART
is still, ultimately, MEANT to be in java.
And here, to prove I'm sane, are a few of those reasons:
, March 18 2005