JOSM no longer working: Exception in thread "main" java.lang.UnsupportedOperationException: Setting a system-wide Policy object is not supported

[Wulf4096]

$ josm
Using /usr/bin/java to execute josm.
2024-11-30 18:09:53.224 INFO: Log level is at INFO (INFO, 800)
Exception in thread "main" java.lang.UnsupportedOperationException: Setting a system-wide Policy object is not supported

at java.base/java.security.Policy.setPolicy(Policy.java:114)
at org.openstreetmap.josm.gui.MainApplication.mainJOSM(MainApplication.java:790)
at org.openstreetmap.josm.gui.MainApplication$3.processArguments(MainApplication.java:280)
at org.openstreetmap.josm.gui.MainApplication.main(MainApplication.java:766)

$ java -version
openjdk version "24-ea" 2025-03-18
OpenJDK Runtime Environment (build 24-ea+26-Debian-1)
OpenJDK 64-Bit Server VM (build 24-ea+26-Debian-1, mixed mode, sharing)

Tried with JOSM 19253 and "latest" (today is 2024-11-30).

I assume it's related to the new java version.

[taylor.smock]

Yes, this is likely related to the EA version of Java 24. If I had to guess, it is specifically related to the deprecation and removal of the SecurityManager. I'll have to install Java 24 EA to be certain, but that is my guess.

[taylor.smock]

In 19264/josm:

Fix #24030: JEP 486 (in Java 24) always throws an UnsupportedOperationException when attempting to set security policy

This merely fixes startup issues. There are a few other locations which may
cause issues, but did not during relatively minimal testing.

[anonymous]

I have this issue after a recent update
===
% josm
2025-03-21 10:04:02.476 INFO: Log level is at INFO (INFO, 800)
Exception in thread "main" java.lang.UnsupportedOperationException: Setting a system-wide Policy object is not supported

at java.base/java.security.Policy.setPolicy(Policy.java:114)
at org.openstreetmap.josm.gui.MainApplication.mainJOSM(MainApplication.java:790)
at org.openstreetmap.josm.gui.MainApplication$3.processArguments(MainApplication.java:280)
at org.openstreetmap.josm.gui.MainApplication.main(MainApplication.java:766)

===

[anonymous]

% pacman -Q josm
josm 19253-1
% java --version
openjdk 24.0.1 2025-03-18
OpenJDK Runtime Environment (build 24.0.1)
OpenJDK 64-Bit Server VM (build 24.0.1, mixed mode, sharing)

[anonymous]

ah, 19253 doesn't have the fix yet =(