Arduino + Java = error “Serial Port Already in Use”

If you try to run the Arduino IDE and the RXTX Java library on MacOS Lion and you are hitting a “Serial Port Already in Use” error,  try:

$ sudo mkdir /var/lock
$ sudo chmod 777 /var/lock

That should hopefully allow you to run them both (though only one at a time!)

If you want  interface your Arduino with the Java, see the Arduino documentation.

4 thoughts on “Arduino + Java = error “Serial Port Already in Use”

  1. Worked great, however I am very curious to know why.
    Do you know any of the technical details?

    From what I can discern: permission were changed. (?)

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