JOSM was originally designed and coded by Immanuel Scholz,
and is now maintained by the OpenStreetMap community.

The current JOSM maintainer is Dirk Stöcker.

Major code contributions from (in alphabetical order):

Stefan Breunig
David Earl
Gabriel Ebner
Dave Hansen
Karl Guggisberg
Jiri Klement
Ulf Lamping
Raphael Mack
Frederik Ramm
Dirk Stöcker

Many minor contributions and patches by others; see SVN history
at http://josm.openstreetmap.de/svn/ for details. Use
"josm-dev AT openstreetmap.org" to contact still active authors.

Copyright rests with the contributors.

The jpeg metadata extraction code is from Drew Noakes
(http://drewnoakes.com/code/exif).

Most icons have been nicked from GNOME and the GIMP, both
under GPL. Some are originally LGPL but redistributed here under 
GPL. The world image is from onearth.pl.

The gettext-commons-0.9.jar is from Felix Berger and Steffen 
Pingel (http://xnap-commons.sourceforge.net/gettext-commons/).
The jar file is licensed under LGPL.

The Bzip2 code is from Keiron Liddle (Apache project) and licensed
with Apache license version 2.0.