Most Java applications don't look the same as C/C++ applications. Swing might have been designed on purpose to have a distincitve look, but based on what I've read, SWT for example tried to 'look native', and doesn't completley succeed.

My question is:

Why is it hard for the developers of the Java language to design a GUI system that copies exactly the look of native GUIs? What's different in native GUIs? Isn't it only a matter of designing buttons that look like 'native' buttons? Or does it go deeper than that?


  Isn't it only a matter of designing buttons that look like 'native' buttons?


Well - sort of, for buttons. But this might be harder than you imagine. These days the graphics used to represent GUI components aren't as simple as random bitmaps that are stretched (since these don't scale very well at all) - they're often vector based graphics with a lot of corner cases programmed into them (so when the button reaches the edge of the screen it may look slightly different, for instance.) And of course, you'll need different graphics when a button is clicked. For copyright reasons, developers often can't just use these existing graphics outright, so they have to be recreated - and while they do a good job for the most part, inevitably some things get missed given the huge array of graphical components out there. This is much less severe than it used to be - these days if I set the default platform look and feel in Swing, I notice very little that looks odd.

I'm saying all the above based on Swing, which is of course a lightweight, non-native GUI toolkit. You specifically mention SWT not looking native, which is a bit odd, because SWT is native. It's a toolkit that uses JNI underneath to call native components - so if something doesn't look right there, it's not going to be because of the look and feel.
