RFC: Introduce JDK property jdk.patched for indicating --patch-module at runtime

[Severin Gehwolf]

Hi,

For JDK-8343839 it would be useful to have some form of API in order to
be able to detect that a currently running Java process has been
launched with '--patch-module'.

Alan Bateman suggested to expose a boolean JDK property to indicate a
runtime that has been launched with --patch-module. In particular, the
suggestion was to use 'jdk.patched' which would be set to true iff
--patch-module is present when the java process launched.

The added benefit would be to have this information available via
serviceability tools as well. For example, -XshowSettings:properties
would be able to show this new property.

Thoughts? Concerns?

Thanks,
Severin