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This page provides help for JOSM on Windows systems.


Using Java Web Start

Java Web Start was deprecated by Oracle in Java SE 9 and removed in Java SE 11, however if you still want to use it, go to the JOSM page and click josm.jnlp. Confirm possible security warnings. This way you will always run the latest version.


There is also the JAR way (download the jar file. double-click the jar file to run it) that will work in most cases. See JOSM/Installation and Java Runtime Environment#How to run a Java application.

There is also a Windows Installer.

Where to put the jar file?

You can put the jar file anywhere, but having a separate folder is a good idea when it comes to organising other files which you may end up placing alongside the jar. On a Windows XP/ME/2000/9x machine you might typically create a folder 'C:\Program files\JOSM' for consistency.

Windows Installer

You may wish to download josm-setup.exe, the windows installer, instead.

When you run this, windows may give you various a security warnings, and then it will guide you through a set-up process which ensures java is installed and gives you a JOSM start menu shortcut. Otherwise, you can set things up to run from a jar file as detailed in the following sections.

Windows command line

The JOSM/Installation instructions talk about running the jar from the command line. Do this in windows by click 'Start' menu -> 'Run...', and enter "cmd" as the name of the program to run.

.bat file

An easy way to avoid fiddling with the command line every time, while still running JOSM with extra command line options, is to place commands in a .bat file.

  • Open the folder where you placed the jar (e.g. 'C:\Program files\JOSM')
  • Right-click to get context menu, then select 'new > Text Document'
  • Set the name 'run-josm.bat' and confirm the change.
  • Open this new file in a plain text editing program.
  • Put your commands here e.g. start javaw.exe -jar -Xmx8192M "C:\Program Files\JOSM\josm-latest.jar"
    • Xmx8192M represents the amount of RAM that will be dedicated (in this case 8GB). You can change the number to whichever you see fit.
    • "C:\Program Files\JOSM\josm-latest" (brackets included) represents the location of the .jar that starts JOSM.
  • ...and save

Double-click the bat file to run JOSM. You should see a black command window each time where the bat file runs. This can be helpful (extra error reporting can appear here sometimes)

CMD script to check for changes in JOSM and download

A cmd script (basically a .bat file) basing the update on the version number is available below. Edit the lines that begin with SET to match your system. curl.exe and unzip.exe are needed for this to run. optional java parameters -Xmx512M sets java to use 512 MB of memory, and -Dsun.java2d.opengl=true to use Open GL graphics acceleration. Remove them if you have any problems.


SET josmver=tested
SET josmjar=josm-%josmver%.jar
SET josmsite=
SET josmpath=c:\documents and settings\username\mapping
SET curlexe=c:\program files\curl\curl.exe
SET unzipexe=c:\program files\zip\unzip.exe
SET tempfile=%temp%\REVISION
SET revfile=%temp%\%josmver%
SET javaopt=-Xmx512M -Dsun.java2d.opengl=true
SET currentrev=0

REM ======= End of config options section =======

"%unzipexe%" -o "%josmpath%\%josmjar%" REVISION -d %temp%
"%curlexe%" %josmsite%/%josmver% -o %revfile%
FOR /f "tokens=1,2" %%A in ('findstr "Revision" %tempfile%') DO SET currentrev=%%B
FOR /f %%A in (%revfile%) DO SET latestrev=%%A
IF NOT %currentrev%==%latestrev% "%curlexe%" %josmsite%/%josmjar% -o "%josmpath%\%josmjar%"

java.exe %javaopt% -jar "%josmpath%\%josmjar%"

Create a shortcut

To create a start menu shortcut to run the latest version of JOSM from the JOSM pages (tested on Windows 10):

  1. Go to C:\Users\%UserProfile%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs
  2. Right click > New > Shortcut
  3. As the location of the item, paste:
    javaws.exe -J-Xmx1G
  4. Choose any name for the shortcut.
  5. Now you can run the shortcut, pin it to the taskbar etc.

In case your shortcut doesn't work, try to reinstall your Java, or put the whole path to your javaws.exe to the shortcut.

Plugins and preferences

When running JOSM for the first time, it will create a folder where plugins are stored. This can be found in a 'My Computer' window by going to "%APPDATA%" (type this in the location bar)

In the 'JOSM' folder inside your Appdata folder you will also find your preferences file. It is named 'preferences.xml'. Note that this is a per-user set of files. If you log on to windows as a different user, you can run JOSM with a different set of preferences and plugins.

Look and feel

JOSM should look like a windows app when it runs. The graphical style of the app can be changed to suite other operating systems, but should be auto-detected as windows when you first run. Other options can be seen in the JOSM 'preferences'