Software requirements

JOSM requires a recent version of ​Java 17 or later runtime environment to be installed on your computer. ​Java 25 or later is preferred.

If you have only an older Java version and cannot update, there were older versions of JOSM available. Unfortunately lacking the new OAuth2 authentication, most of them will no longer work.

• Version 3377 for Java 5.
• Version 7000 for Java 6.
• Version 10526 for Java 7.
• Version 18969 for Java 8.
• Version 19678 for Java 11.

Old versions of JOSM, including Mac and Windows installers, are available in the download archive. However it is highly recommended to always use the latest stable version.

Troubleshooting

• Launching JOSM on the command line outputs

  Exception in thread "main" java.lang.UnsupportedClassVersionError: JOSM : Unsupported major.minor version 52.0
  

  → Make sure to install the Java version described above.

Hardware requirements

It will heavily depends on the workflow, installed plugins, active mappaint styles, amount of loaded data and imagery in use.

But it is feasible to use JOSM on computers with parameters such as 512 MB of RAM.