JOSM hangs on startup and gives an error message. see screenshot.

[hpduwe@…]

What steps will reproduce the problem?

What is the expected result?

What happens instead?

JOSM hangs on startup and gives an error message.

see screenshot./home/hpduwe/Bilder/Bildschirmfoto von 2022-07-25 11-49-26.png/home/hpduwe/Bilder/Bildschirmfoto von 2022-07-25 11-49-26.png

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2022-07-07 23:02:39 +0200 (Thu, 07 Jul 2022)
Revision:18513
Build-Date:2022-07-08 01:30:57
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (18513 de) Linux Ubuntu 20.04.4 LTS
Memory Usage: 79 MB / 960 MB (30 MB allocated, but free)
Java version: 11.0.15+10-Ubuntu-0ubuntu0.20.04.1, Private Build, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.metal.MetalLookAndFeel
Screen: :0.0 1366×768 (scaling 1.00×1.00)
Maximum Screen Size: 1366×768
Best cursor sizes: 16×16→16×16, 32×32→32×32
Environment variable LANG: de_DE.UTF-8
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: de_DE
Numbers with default locale: 1234567890 -> 1234567890
Desktop environment: ubuntu:GNOME
Java package: openjdk-11-jre:amd64-11.0.15+10-0ubuntu0.20.04.1
Java ATK Wrapper package: libatk-wrapper-java:all-0.37.1-1
fonts-noto: fonts-noto:all-20200323-1build1~ubuntu20.04.1
VM arguments: [--module-path=/usr/share/openjfx/lib, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, -Djosm.restart=true, -Djava.net.useSystemProxies=true, --add-exports=java.base/sun.security.action=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED]

Plugins:
+ FixAddresses
+ HouseNumberTaggingTool
+ Lanes
+ Tracer2
+ buildings_tools
+ turnlanes

Last errors/warnings:
- 00003.591 E: Exception raised in EDT: java.util.concurrent.ExecutionException: java.lang.ExceptionInInitializerError. Ursache: java.lang.ExceptionInInitializerError. Ursache: java.lang.NullPointerException
- 00003.603 E: Exception raised in EDT: java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: Could not initialize class org.openstreetmap.josm.actions.SessionSaveAction. Ursache: java.lang.NoClassDefFoundError: Could not initialize class org.openstreetmap.josm.actions.SessionSaveAction
- 00033.261 E: Handled by bug report queue: java.lang.NoClassDefFoundError: Could not initialize class org.openstreetmap.josm.actions.SessionSaveAction



=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: main (1)
java.lang.NoClassDefFoundError: Could not initialize class org.openstreetmap.josm.actions.SessionSaveAction
	at org.openstreetmap.josm.gui.MainMenu.<init>(MainMenu.java:181)
	at org.openstreetmap.josm.gui.MainFrame.initialize(MainFrame.java:93)
	at org.openstreetmap.josm.gui.MainApplication.initializeMainWindow(MainApplication.java:415)
	at org.openstreetmap.josm.spi.lifecycle.InitializationTask.call(InitializationTask.java:33)
	at org.openstreetmap.josm.spi.lifecycle.Lifecycle.runInitializationTasks(Lifecycle.java:103)
	at org.openstreetmap.josm.spi.lifecycle.Lifecycle.initialize(Lifecycle.java:71)
	at org.openstreetmap.josm.gui.MainApplication.mainJOSM(MainApplication.java:953)
	at org.openstreetmap.josm.gui.MainApplication$3.processArguments(MainApplication.java:277)
	at org.openstreetmap.josm.gui.MainApplication.main(MainApplication.java:741)

[taylor.smock]

Closed as duplicate of #22183.
@hpduwe: Can you run JOSM with --trace and paste stack traces only in #22183? (--trace may expose sensitive information)?

josm --trace should do it.

[taylor.smock]

In 18570/josm:

Fix #22183: NoClassDefFoundError: Could not initialize class org.openstreetmap.josm.actions.SessionSaveAction

This was caused by JOSM detecting that it had started in IPv6 mode, but no IPv6
network was available. When this occurs, JOSM immediately sets a preference key
and restarts so that users are not confused about a lack of network connectivity.

The JOSM restart action then proceeds to attempt to save any active layers, but
since this occurs during startup, there are no active layers and the save actions
have not yet been initialized. The save actions cannot be initialized before
contentPanePrivate has been initialized, but the IPv6 call is done prior to
that happening, which may then trigger a JOSM restart, which calls exitJosm,
which then calls the save layers actions.