Document how JAVA_OPTS can be used with the buildpack

[philwebb]

See #21483 (comment)

[fernandezseb]

Hey, I'd like to take on this task if that's okay.

[nebhale]

@philwebb We can do some additional documentation in our buildpacks as well to help with this as well.

[snicoll]

We can document something on our side but I wonder if that's a good idea. By the time this issue was created, this was already renamed and the references above are outdated.

Looking at paketo-buildpacks/bellsoft-liberica@06551ec#diff-04c6e90faac2675aa89e2176d2eec7d8 it looks like the property to use now is JAVA_TOOL_OPTIONS.

[philwebb]

@nebhale It does feel like some more user-facing Packeto documentation that we could link to would be very useful.

[nebhale]

Yep, first thing on my list either during my downtime this week or just after SpringOne. The entire Paketo team is adding that as we speak.

[scottfrederick]

Paketo buildpacks documentation has been updated, so the Spring Boot docs can now link to the relevant section in paketo.io: https://paketo.io/docs/buildpacks/language-family-buildpacks/java/#runtime-jvm-configuration.

We should include a disclaimer that the information provided by this link only applies when the Paketo builder and buildpacks are used, and other CNB implementations might work differently.