This was captured in Terminal "WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.bulenkov.darcula.DarculaLaf (file:/Applications/Moneydance.app/Contents/Java/darcula.jar) to constructor com.apple.laf.AquaLookAndFeel()
WARNING: Please consider reporting this to the maintainers of com.bulenkov.darcula.DarculaLaf
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release"
While I'm not a Mac user I will make a couple of comments
1. Moneydance comes bundled with a specific version of Java that it uses, it will not use any installed system Java.
2. I believe Apple have changed directory structures with Big Sur. with the upper level Moneydance location something like /Users/<username>/Library/Containers/Moneydance/Data/
If you have any trouble finding your Home Library folder you can open Finder and hold down the option key while selecting the Go menu and the Library folder option should occur or you can open Finder and select Go → Go to Folder and copy and paste in the following:
This should pull up your local Library folder.
You could also potentially use Finder to see if you can locate the file errlog.txt
iCloud support for the desktop was introduced in one of the Moneydance 2021 preview releases, I have seen no reports of any problems with it.
Big Sur shouldn't be a problem since that's what I've been using for development, and there's nothing specific to recent iCloud Drive APIs in use here anyway.
For anyone having this problem, could you go to System Preferences, select the "Apple ID" section, and check the "Apps on this Mac using iCloud" list to see if iCloud Drive is enabled? In addition, if you click the "Options..." button next to iCloud Drive, does the Moneydance entry lin the window that appears have a checked checkbox next to it?
If I unset iCloud Drive or unset "Apps on this Mac using iCloud", restart MD, then when selecting iCloud sync I see message: ICloudContainer.isContainerAvailable(): nativeGetICloudPath: null message (but there is no java crash..
One more question for those seeing this crash: Do you remember if Moneydance is set to re-open the last file upon launch, or does it bring you to the "Welcome to Moneydance" window that shows a list of files and some opening/import options?