freeplane always crashes when running with openjdk-25-jre or openjdk-26-jre,
running with:

env JAVA_HOME=/usr/lib/jvm/java-25-openjdk-amd64 freeplane
env JAVA_HOME=/usr/lib/jvm/java-26-openjdk-amd64 freeplane

The exception is:

java.lang.UnsupportedOperationException: Setting a system-wide Policy object is
not supported
        at java.base/java.security.Policy.setPolicy(Policy.java:114)
        at
org.freeplane.plugin.script.ScriptingPolicy.installRestrictingPolicy(ScriptingPolicy.java:112)
        at
org.freeplane.plugin.script.ScriptingRegistration.register(ScriptingRegistration.java:184)
        at
org.freeplane.plugin.script.ScriptingRegistration.<init>(ScriptingRegistration.java:142)
        at
org.freeplane.plugin.script.Activator$1.installExtension(Activator.java:26)
        at
org.freeplane.main.osgi.ActivatorImpl$OsgiExtentionInstaller.installExtensions(ActivatorImpl.java:280)
        at
org.freeplane.main.osgi.ActivatorImpl.installControllerExtensions(ActivatorImpl.java:296)
        at
org.freeplane.main.osgi.ActivatorImpl.startFramework(ActivatorImpl.java:215)
        at org.freeplane.main.osgi.ActivatorImpl.start(ActivatorImpl.java:109)
        at org.freeplane.main.osgi.Activator.start(Activator.java:35)
        at org.knopflerfish.framework.BundleImpl.start0(BundleImpl.java:386)
        at org.knopflerfish.framework.BundleThread.run(BundleThread.java:145)


Newer upstream version 1.13.x won't fix this. It looks like that Freeplane uses
the obsolete Java security manager, so even the latest freeplane doesn't run
with Java 24 or later.
(https://github.com/freeplane/freeplane/discussions/2124)

Hello,

Bug #1128209 in freeplane reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/java-team/freeplane/-/commit/64b7a7cd7e6e7ffb1aa869d5a51ea3ffa99cf408

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1128209

We believe that the bug you reported is fixed in the latest version of
freeplane, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1128209@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Emmanuel Bourg <ebourg@apache.org> (supplier of updated freeplane package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 18 Oct 2026 13:06:48 +0200
Source: freeplane
Architecture: source
Version: 1.7.10-3
Distribution: unstable
Urgency: medium
Maintainer: Debian Java Maintainers <pkg-java-maintainers@lists.alioth.debian.org>
Changed-By: Emmanuel Bourg <ebourg@apache.org>
Closes: 985597 1128209 1137396 1148904
Changes:
 freeplane (1.7.10-3) unstable; urgency=medium
 .
   * Team upload.
   * Don't quote the %-escapes in the mailcap entries (Closes: #985597)
   * Fixed the build failure with bnd 5.1+ (Closes: #1137396)
   * Fixed the startup with Java 24+ (Closes: #1128209)
   * Tightened the dependency on simplyhtml (Closes: #1148904)
   * Converted debian/watch to the version 5 format
   * Standards-Version updated to 4.7.4
   * Removed the Priority field
   * Removed the Rules-Requires-Root field
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