What are custom JVM properties: Java has its own concept of environment variables for whatever reason.

How can I obtain the system properties for a particular JVM instance programmatically?

I downloaded a JVM zip, unpacked it, and then used jcmd.

$ Get-Process pycharm64

 NPM(K)    PM(M)      WS(M)     CPU(s)      Id  SI ProcessName
 ------    -----      -----     ------      --  -- -----------
    268 1,556.25   1,759.14     151.31    2092   1 pycharm64  

$ .\jcmd.exe 2092 VM.system_properties
2092:
...
idea.cycle.buffer.size=1024
idea.dynamic.classpath=false
idea.fatal.error.notification=disabled
idea.max.content.load.filesize=20000
idea.max.intellisense.filesize=2500
idea.no.launcher=false
idea.paths.selector=PyCharm2023.2
...