RFR: 8359808: JavaRuntimeURLConnection should only connect to non-directory resources [v3]

[David Beaumont]

On Fri, 20 Jun 2025 11:13:12 GMT, David Beaumont <duke at openjdk.org> wrote:

>> Simplifying JavaRuntimeURLConnection to avoid accidentally returning non-resource data to users.
>> 
>> This change has the following distinct parts:
>> 1. Refactor code to use Node instead of directly accessing low level ImageLocation type.
>> 2. Remove unnecessary use of "Resource" interface and related URL generation code (completely unreachable).
>> 3. Adding comments explaining why there's a non-obvious distinction in how module and resource names are treated with respect to URL percent encoding.
>> 4. Small constructor logic simplification (module name cannot be null anymore)
>> 5. Small simplification around 'READER' use, since it is impossible for that to ever be null (other users of ImageReaderFactory already assume it could never be null, and code path analysis agrees).
>> 6. Adding tests for the non-resource cases.
>> 7. Adding extra test data to check the behaviour with respect to things like percent escaping (previously untested).
>> 8. Adding TODO comments for things I could do in this PR or later (reviewer opinions welcome).
>
> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Feedback changes and renaming field to match nomenclature of JEP 220.

Updated wrt to comments, but still a couple of outstanding questions:
1. InternalError vs MalformedURLException for "junk" input (raised by Roger) ?
2. Not 100% sure about Alan's comment (now outdated) "If the URL scheme from JEP 220 goes into the first comment then it will be clear that the resource is optionally."
3. Should I revert the explicit fast-path test until some non-default percent encoding logic is decided upon (raised by Roger) ?

Other than that, I think I've covered everything.

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PR Comment: https://git.openjdk.org/jdk/pull/25871#issuecomment-2996019859