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

The current JOSM maintainer is Dirk Stöcker.
A lot of administration work is done by Paul Hartmann and Vincent Privat.

Major code contributions from (in alphabetical order):

Stefan Breunig
David Earl
Gabriel Ebner
Dave Hansen
Paul Hartmann
Karl Guggisberg
Matthias Julius
Alexei Kasatkin
Jiri Klement
Ulf Lamping
Simon Legner
Raphael Mack
Upliner Mikhalych
Gerd Petermann
Vincent Privat
Frederik Ramm
Dirk Stöcker
Stefan Volke
Michael Zangl

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

The logo has been designed by Ilya Palikov.

Copyright rests with the contributors.

-------------------------------- EXTERNAL CODE --------------------------------

The jpeg metadata extraction code is from Drew Noakes
(https://github.com/drewnoakes/metadata-extractor) and licensed
with Apache license version 2.0.

The Bzip2 code is from Apache Commons Compress and licensed
with Apache license version 2.0.

The signpost code (http://code.google.com/p/oauth-signpost/)
is from Matthias Käppler and licensed with the Apache License 2.0.

The mail/url validator routines use code from Apache Commons
Validator which is licensed with Apache license version 2.0.

The NTv2 transformation code (http://jgridshift.sourceforge.net/)
is from Peter Yuill and licensed with LGPL.

The MultiSplitPane is from Hans Muller and licensed with LGPL
(https://today.java.net/pub/a/today/2006/03/23/multi-split-pane.html).

The Alphanum Algorithm is from David Koelle and license with MIT
(http://www.davekoelle.com/alphanum.html)

The Diff code (http://www.bmsi.com/java/#diff) 
is from Stuart D. Gathman and licensed with GPL.

The Ellipsoid code (http://www.i3s.unice.fr/~johan/gps/)
is from Johan Montagnat and licensed with GPL.

The JSON code (https://javaee.github.io/jsonp/)
is from Oracle (RI for JSR 374: Java API for JSON Processing) 
and licensed with GPL / classpath exception.

The opening hour validation uses OpeningHoursParser
(https://github.com/simonpoole/OpeningHoursParser) which is licensed
with MIT.

The XZ code (https://tukaani.org/xz/java.html)
is from Lasse Collin and Igor Pavlov
and license free Public Domain.

The Windows shortcut parsing code is from StackOverflow:
- https://stackoverflow.com/a/9403438/2257172
- https://github.com/codebling/WindowsShortcuts

The gui/animation Christmas GPL code is from Jiri Vanek (Red Hat):
- http://icedtea.classpath.org/hg/icedtea-web/rev/87d3081ab573

------------------------------- PROJECTION DATA -------------------------------

Australian A66_National NTV2 grid: Source: Intergovernmental Committee on
                                           Surveying and Mapping (CC BY 4.0)

British OSTN02 NTV2 grid: Source: Ordnance Survey (BSD)
© Crown copyright, Ordnance Survey and the Ministry of Defence (MOD) 2002.
All rights reserved.

French NTF_R93 NTV2 grid: Source: IGN - Institut national de l'information
                                        géographique et forestière

German BETA2007 NTV2 grid: Source: BKG - Bundesamt für Kartographie und Geodäsie

Portuguese HGDLx / HGD73 NTV2 grids: Source: Direção Geral do Território

Swiss CHENYX06 NTV2 grid: Source: Swiss Federal Office of Topography

ESRI projection definitions: Environmental Systems Research Institute

------------------------------------ ICONS ------------------------------------

Lots of icons are from GNOME Project https://www.gnome.org/ under GPL or LGPL,
redistributed here under GPL.

Some icons are from GIMP https://www.gimp.org/ under GPL or LGPL,
redistributed here under GPL.

Lots of icons are from https://openclipart.org/, https://publicdomainvectors.org/,
The Tango Desktop Project, other sources or self created, all PD and CC0 licensed.

Simple OpenStreetMap logo has been created by ScubbX (CC-SA 2.0) based on official
logo used by the OpenStreetMap Foundation:
https://wiki.openstreetmap.org/wiki/File:Logo_simple.svg

Social logos come from https://github.com/Automattic/social-logos (GPLv2 or later)

The keyboard icon comes from:
- source: http://www.iconfinder.net/index.php?q=key&page=icondetails&iconid=8553&size=128&q=key&s12=on&s16=on&s22=on&s32=on&s48=on&s64=on&s128=on
- licence: GPL
- designer: Paolino, http://www.paolinoland.it/
- original filename: keyboard.png
- original size: 128x128
- modifications: icon was cropped, then resized

See also the commit message of each icon for its source
(https://josm.openstreetmap.de/browser/josm/trunk/resources/images).