Software requirements

JOSM requires a recent version of ​Java 11 or later runtime environment to be installed on your computer. ​Java 21 or later is preferred.

If you have only an older Java version and cannot update, there were older versions of JOSM available. Unfortunately, most of them will no longer work after June 01, 2024.

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

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.

If you have only an old version of Java 7 (older than update 25, released in June 2013), you can run version 10526 of JOSM, but you may face the following Java bug. To get rid of it, please perform the corresponding update actions.

• #8182: Mac OS: Cannot open files in directories with swedish characters in them -> Update to Java 7 update 10 or later (see ​Java bug 7193966)

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.