I used Arduino successfully on my old Linux Fedora 12 system. Now I have a brand new PC with Fedora 20, and have today installed Arduino on it. In my first attempt to use it I typed Arduino as follows at the root prompt, after the "yum install arduino" gave me "Complete!", as follows:

[1344][root@localhost:/home/Harry]# arduino
WARNING:  RXTX Version mismatch
    Jar version = RXTX-2.2
    native lib Version = RXTX-2.2pre2

Subsequently I have loaded the "Blink" sketch, and that is running nicely, whether I start the IDE from the command line, which still gives me the same WARNING, or from the desktop icon, which does not give it.

So my question is: please, does this WARNING matter? If so, what should I do about it?


The warning, as I'm sure you can tell, is about a mismatch in version of RXTX arduino is expecting, and what is installed on your system. If everything is functioning, I would not worry about it at all. The versions seem to only be slightly different, maybe just a few bug fixes are missing from the older one.

RXTX is a library for java to communicate with serial devices, but it is not under development anymore and only available from mirrors, not the original developer site. Arduino has moved on to a library called jSSC, which is currently being maintained, and a much better library IMHO. The change to jSSC is still only in the arduino beta version, 1.5.6r2 at time of writing, but it works very well. Anyway, if RXTX ever actually gives you trouble, you can download the beta version of arduino and not have to deal with it.

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  • An excellent answer, covers it nicely for me, thanks. – Harry Weston May 29 '14 at 21:47

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