[isabelle-dev] NEWS: Update to OpenJDK 21

[Makarius]

On 20/11/2023 22:23, Makarius wrote:
> *** System ***
> 
> * Update to OpenJDK 21: the current long-term support version of Java.
> 
> Moreover, it might be time to change a few fundamental Java runtime defaults, 
> e.g. ZGC https://openjdk.org/jeps/439

My overall impression is that ZGC requires more heap space (due to full 64bit 
pointers) and cumulatively more GC time. At that cost it promises better 
reactivity.

Here is an example for $ISABELLE_HOME_USER/etc/settings for further 
experimentation:

JEDIT_JAVA_OPTIONS="-Xms512m -Xmx8g -Xss16m -XX:+UseZGC -XX:+ZGenerational 
-XX:SoftMaxHeapSize=2g"


	Makarius