RFR: 8368333: [lworld] Add preview mode to ImageReader and JRT file-system [v7]

[David Beaumont]

On Tue, 14 Oct 2025 18:28:48 GMT, David Beaumont <duke at openjdk.org> wrote:

>> Java changes for supporting preview mode when preview mode resources (with new location flags) are available.
>> 
>> At the moment, this code will operate on non-preview jimage files (1.0) and act as if no preview resources are available by virtue of the default value for missing attributes and package flags being zero (which matches jimage 1.0).
>> 
>> This should be reviewed on top of https://github.com/openjdk/valhalla/pull/1618
>
> David Beaumont has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:
> 
>  - Rolled up changes after rebase.
>    
>    * Removing package root flag based on feedback.
>    * Changing existing package flags during writing to match altered flag values.
>    * Feedback changes, and fixing some comments.
>    * Renaming slightly confusing "testEncoder" method.
>    * Fixing unit tests to use new constructor.
>    * Word smithing flags definitions.
>    * Add workaround until new image writing code is in
>    * Clarifying flag docs for /packages/xxx case
>    * Java ImageReader changes for preview mode
>  - Merge branch 'jdk_8366093_cpp/squashed' into jdk_8368333_java/squashed
>  - [[RESET BRANCH FOR MERGE]]
>  - Removing package root flag based on feedback.
>  - Changing existing package flags during writing to match altered flag values.
>  - Feedback changes, and fixing some comments.
>  - Test fixes and feedback changes.
>    
>    * Renaming slightly confusing "testEncoder" method.
>    * Fixing unit tests to use new constructor.
>  - Manually deleting ImageReaderFactory (it returned somehow)
>  - Word smithing flags definitions.
>  - Add workaround until new image writing code is in
>  - ... and 2 more: https://git.openjdk.org/valhalla/compare/a993aa4a...9bbc26c1

test/jdk/tools/jimage/ImageReaderDuplicateChildNodesTest.java line 2:

> 1: /*
> 2:  * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.

Restoring the copyright year accidentally removed in the last change.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1619#discussion_r2430086433