Jar and jad

Question

Hello community!
I've been dealing with the wireless toolkit for a couple of days now, mostly trying some game technique implementations... my question is: I have to upload the jar and the descriptor to my mobile phone, right? Which one do I have to "install"? If I install the jar everything works fine. When I try to install the jad file the phone produces some sort of "download error". If I do not copy the jad file to my phone at all there are no problems. So what is the use of these jad's after all? Okay, they're archive descriptors but the same information is stored in the archive's manifest... (JBuilder does it for me)
regards
Steffen

Answer 1

If we talk about MIDP implementations, then the most common approach is that when you load an image into memory it gets converted to the phone's native color format. I don't have a 6600, but I can tell you that that's what the rest of the Nokias (and many other devices) I've tried do. So once the image has been loaded the performance would be optimal since it's already been converted (with an adverse impact in heap usage though).
In my experience preconverting the images to the phones color format hasn't really been necessary. The difference in loading times has been insignificant. The savings in application size that come from using paletized images mostly outweigh the loading-time issues. And since phones don't have one format used in every one, customizing images for specific devices can become very tedious (there are just so many devices out there). Unless you're loading and unloading the images constantly, which is a bad idea anyway for a myriad of other reasons, I hardly think that it's necessary to preconvert them.
In short, the main concern when dealing with images tends to be with the jar space they take up and not the time it takes to load them. But it is a device-specific issue, so there is no iron rule.
shmoove