jjmpeg - why java?
As a follow-up to the post about using Java and JNI to access ffmpeg, perhaps the more fundamental query is - why use Java in the first place? After all, Java is slow and crappy and nobody uses it anyway and isn't .NET the way to go and all that?
I used to write Amiga BOOPSI classes in assembler for fuck's sake, so why am I now using Java?
For starters Java is not slow - although as with any language you can (un)intentionally make it slower than necessary. Compared to similar systems with the same application support it isn't bulky; at run-time or on disk. The JVM is mature and stable and the garbage collection is reliable and fast.
Machines are also not slow these days - in-fact they are so fast most of the processing power is wasted much of the time. Likewise for memory. Wasted processing cycles and wasted memory bytes are actually an inefficiency, not necessarily something to chime about. I am no longer developing applications for a 1MB system running a multitasking GUI. Nobody is.
I still enjoy writing C, and I am still concerned with performance and efficiency, but I have been using Java for a few years now and am very happy with it - and I continue to be further pleasantly surprised from time to time. I find it puzzling that far more desktop software isn't written using Java - in my experience it compares well in all the important categories and is generally easier to develop for.
For example, performance is usually within a few % of C for normal scalar, single-threaded C. Most programmers don't seem capable of going beyond that type of code anyway - and those that are will find JNI a piece of piss. It will probably require twice as much memory - but this is simply an artefact of the use of a decently fast garbage collector - nothing comes completely free, but with memory expanding so much in recent years this is about the cheapest cost you could imagine for the huge benefit it provides. And I don't just mean no longer needing to track which pointers to free - I never found that particularly onerous although many people are unable to grok it - the GC is also a very fast memory allocator as well. No need for pool or slice allocators and the whatnot.
By the time you add all of the features of a basic JVM runtime to C (or anything else), you have something like GNOME or KDE which are not very small at all, have large memory footprints themselves, and are still not as easy to work with (speaking of GNOME as of some time ago at least, I haven't tried KDE and in any event loathe C++ so am not about to).
Of course, python (or ruby) seem to be the flavour of the month at the moment, but they have their own issues. Usually they are just ugly front-ends to some C libraries or commands and they have the same problems that tcl/tk scripts had - a specific version dependency, ugly gui's, and meaningless error messages from their inevitable crashes. And for all that they're not particularly robust, nor provide a particularly compact memory footprint.