8332074: Create a "jdk.exploded" test property to check if the testee jdk is exploded

[tstuefe]

Since we cannot run CDS operations on an exploded JDK, excluding tests like these for exploded JDKs makes sense.

However, being an exploded JDK is not the same as not having CDS built into the JVM. Plus, exploded JDKs have effects beyond their inability to run with CDS. Therefore a property makes sense.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8332074: Create a "jdk.exploded" test property to check if the testee jdk is exploded (Enhancement - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/19178/head:pull/19178
$ git checkout pull/19178

Update a local copy of the PR:
$ git checkout pull/19178
$ git pull https://git.openjdk.org/jdk.git pull/19178/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 19178

View PR using the GUI difftool:
$ git pr show -t 19178

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/19178.diff

[bridgekeeper]

👋 Welcome back stuefe! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

@tstuefe The following labels will be automatically applied to this pull request:

• core-libs
• hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

[AlanBateman]

This looks useful. I just wonder about the terminology. We usually speak of an exploded image or exploded build, just reacting to the name and the comment that it checks "whether the test JDK is exploded".

[magicus]

There is a long standing build infra bug about changing "JDK exploded". First of all, the name is not at all fitting for what it really is, so the proposal is to rename it to a "partial JDK". Secondly, there are different opinions on what should be included in a partial JDK, so the concept might be expanded to allow for building different kinds of partial JDKs with different amount of functionality present.

I did a quick search but could not find the associated JBS issue, but it is there somewhere.

[magicus]

This also means that I think the solution you did in JDK-8332105 is superior to this, where you test for the individual functionality you want. Adding a broad "jdk exploded" property to the tests will only complicate matters if/when we support multiple kinds of partial JDKs.

[tstuefe]

@magicus convinced me that this is not a good idea.