Java memory/version issue [edited].

[MarmiteSandwich]

I have a Raspberry Pi which is exhibiting periodic memory problems. Over time, memory seems to be getting used up. See memory usage chart.
Experimenting with top over a period of 9 days indicated that 2 java applications, MS and BubbleUPnP Server, were the culprits, although MS was worse.    

I use OpenMediaVault to manage the server and I have recently upgraded to OMV6. In the process, java seems to have been upgraded to 11.

Code:

pi@raspifaircross:~ $ java -version
openjdk version "11.0.22" 2024-01-16
OpenJDK Runtime Environment (build 11.0.22+7-post-Raspbian-1deb11u1)
OpenJDK Server VM (build 11.0.22+7-post-Raspbian-1deb11u1, mixed mode)

I have another Pi with MS and Java 8, which does not seem to display these memory charcteristics.
Is there an issue with the version of Java, or is there some Java setting needed to prevent these memory usage chracteristics?
Marmite
Edit: correct memory usage chart added