Re: Write once, run anywhere?

From:

Mark Space <markspace@sbc.global.net>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 23 Jun 2007 10:57:13 -0700

Message-ID:

<6adfi.21578$C96.19561@newssvr23.news.prodigy.net>

JT wrote:

(classes)? Let's say we have two operating systems, x and y.
OS x has a way to oh say... open the CD tray. OS y does not. So would
a JVM running on x include an implementation of the openCDTray and y
would not, or would it be excluded on both since it's not a common

I'll repeat what Jeff and Josh said. If there's no way to open a CD
tray, then there's no way to do it. You might be able locate a utility
or library function that does it for you. The java.lang.Runtime object
allows you to exec( String ) for the OS to execute. That's a simple way
to call an OS dependent feature. If the call fails, you can try a
different one that may work on OS y, or just give up and return an error.

If you really have to get down and dirty, there's JNI, which will let
you call native code. Break out the C compiler and do it yourself, or
locate a library (DLL, SO, etc.) that does what you want.

Then there's "creative laziness." Use Swing. Put up a dialog box
telling the user to press the CD eject button and insert the correct
disk now. Click ok when done. This works for any OS. ;)