current JOSM requires java 7; the last java available direct from apple was java 6, so you’ll need a java 7 installer from Obstacle, er, Oracle to pull this off. but it worked just fine on my old (2007) macbook pro (OS X Lion) and it is now working fine on my new Macbook air (OS X Mavericks)
Discussion
Comment from Marián Kyral on 18 August 2014 at 19:12
http://wiki.openstreetmap.org/wiki/JOSM/Mac
Comment from smsm1 on 18 August 2014 at 19:35
I just use the Java webstart file to start JOSM on my Mac.
I download the .jnlp file from http://josm.openstreetmap.de The nice thing about JNLP is that you automatically get updates to the software.
Comment from baprischka on 18 August 2014 at 19:45
I’m running JOSM on a Mac, just download the zip and move the JOSM.app file in your Applications folder
Comment from nfgusedautoparts on 7 September 2014 at 01:17
current JOSM requires java 7; the last java available direct from apple was java 6, so you’ll need a java 7 installer from Obstacle, er, Oracle to pull this off. but it worked just fine on my old (2007) macbook pro (OS X Lion) and it is now working fine on my new Macbook air (OS X Mavericks)