fix: try-with-resources for Streams interacting with Files to ensure proper resource management (#4404)
# Description of Changes
The Javadoc recommends wrapping Files.list(), Files.walk(),
Files.find(), and Files.lines() in try-with-resources so the stream’s
close() is called as soon as the terminal operation completes.
This is because when Stream interact with files, Java can ONLY close the
Stream during garbage-collection finalization, which is not guaranteed
to run promptly or at all before the JVM exits, creating a memory leak.
Direct quote:
> Streams have a
[BaseStream.close()](https://docs.oracle.com/javase/8/docs/api/java/util/stream/BaseStream.html#close--)
method and implement
[AutoCloseable](https://docs.oracle.com/javase/8/docs/api/java/lang/AutoCloseable.html),
but nearly all stream instances do not actually need to be closed after
use. Generally, only streams whose source is an IO channel (such as
those returned by [Files.lines(Path,
Charset)](https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#lines-java.nio.file.Path-java.nio.charset.Charset-))
will require closing. Most streams are backed by collections, arrays, or
generating functions, which require no special resource management. (If
a stream does require closing, it can be declared as a resource in a
try-with-resources statement.)
> A DirectoryStream is opened upon creation and is closed by invoking
the close method. Closing a directory stream releases any resources
associated with the stream. Failure to close the stream may result in a
resource leak. The try-with-resources statement provides a useful
construct to ensure that the stream is closed:
Sources:
https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/nio/file/DirectoryStream.html
https://stackoverflow.com/questions/79078272/using-try-with-resources-for-a-java-files-walk-stream-created-in-a-separate-meth
https://stackoverflow.com/questions/36990053/resource-leak-in-files-listpath-dir-when-stream-is-not-explicitly-closed
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---
## Checklist
### General
- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings
### Documentation
- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)
### UI Changes (if applicable)
- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)
### Testing (if applicable)
- [x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.
---------
Signed-off-by: Balázs Szücs <bszucs1209@gmail.com>
