Ad-Hoc Java System Properties

You've always been able to add ad-hoc Java system properties for a server in your server.json via jvm.args in the format of -Dfoo=bar. There is also a top-level struct that is more readable which does the same thing:
"jvm" : {
"properties" : {
"foo" : "bar baz"
"java.awt.headless" : "true"
No additional quoting or escaping is needed for spaces or special characters when using this method.
Set these programmatically like so:
server set
Or set them globally for all servers in your config setting server defaults.
config set
Keys will be merged, giving precedence to the server.json values.