Proposal: Remove support for running JavaFX with the security manager

[Kevin Rushforth]

The Java Security Manager was deprecated for removal in JDK 17 by JEP 
411 [1]. The next step in the evolution of removing the security manager 
is to permanently disable it as proposed by candidate JEP 486 [2]. Once 
this is done, System::getSecurityManager will unconditionally return 
null, System::setSecurityManager will unconditionally throw 
UnsupportedOperationException, and running "java -Dsecurity.manager" 
will cause the VM to exit with a fatal error. This will either happen in 
JDK 24 (likely) or 25 (in case it misses 24). Either way, it will soon 
be gone.

I propose to remove support for running JavaFX applications with a 
security manager in JavaFX 24. Any JavaFX application that uses a 
security manager will necessarily need to use JDK 21.x LTS going 
forward, and thus can similarly use JavaFX 21.x LTS. See JDK-8341090 [3].

Comments?

-- Kevin

[1] https://openjdk.org/jeps/411
[2] https://openjdk.org/jeps/486
[3] https://bugs.openjdk.org/browse/JDK-8341090