Switch code style to Google's Java Code Style

[koppor]

I am so fed up that

• contributors are not able to configure IntelliJ properly (e.g., [WIP] This relativizes the PDF's filepaths after importing through "Find Unlinked Files" JabRef/jabref#10582). We tried OpenRewrite for auto fixing, but did not work.
• our reformatting broke a few months ago for exceptions (e.g., Display files from referenced crossref in entry table (Toro520 version) JabRef/jabref#10577 (review))

Thus, I am looking for good autoformatting tools. The most prominent tool with style guide is Google's:

• Google's Java Code Style (in the AOSP variant) provides a nice formatting.
• Google's Java Format toolchain provides auto format. See https://github.com/axel-op/googlejavaformat-action#google-java-format-action

This PR adds it.

Let's hope for the best that the reformatting action a) really adds a new commit and b) the contributors will be able to pull these changes 😅🙈

I am aware, that there is no maintained gradle plugin.

I am also aware, that there is no AOSP support for Eclipse since 5 years (google/google-java-format#251), but maybe, this will be resolved.

One needs to run it twice for coments: google/google-java-format#211

---

Blockers

• Unexpectedly change the AST google/google-java-format#980

Mandatory checks

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[Siedlerchr]

Mabye spotless ? https://github.com/diffplug/spotless

[koppor]

• spotless has issues with Gradle 8: Bug: Spotless gradle plugin execution fails with Gradle 8.0 diffplug/spotless#1572 (comment)
• spotless fails if code style is not met -- linting support is future work: obsolete - Add support for linters diffplug/spotless#1097

Wait for another PR - I have success with palantir-java-format.

That is a) more maintained and b) seems to work well and c) has better formatting than GJF:

(1) google-java-format output:

private static void configureResolvedVersionsWithVersionMapping(Project project) {
    project.getPluginManager()
            .withPlugin(
                    "maven-publish",
                    plugin -> {
                        project.getExtensions()
                                .getByType(PublishingExtension.class)
                                .getPublications()
                                .withType(MavenPublication.class)
                                .configureEach(
                                        publication ->
                                                publication.versionMapping(
                                                        mapping -> {
                                                            mapping.allVariants(
                                                                    VariantVersionMappingStrategy
                                                                            ::fromResolutionResult);
                                                        }));
                    });
}

(1) palantir-java-format output:

private static void configureResolvedVersionsWithVersionMapping(Project project) {
    project.getPluginManager().withPlugin("maven-publish", plugin -> {
        project.getExtensions()
                .getByType(PublishingExtension.class)
                .getPublications()
                .withType(MavenPublication.class)
                .configureEach(publication -> publication.versionMapping(mapping -> {
                    mapping.allVariants(VariantVersionMappingStrategy::fromResolutionResult);
                }));
    });
}

---

• Update One can see the difference also at that PR: https://github.com/Sparky983/vision-gui/pull/219/files
• Update Google won't fix it: odd formatting for lambdas google/google-java-format#19

[koppor]

New try at #663

[koppor]

I applied the binary from https://github.com/google/google-java-format/releases/tag/v1.24.0

MINGW64 /c/git-repositories/jabref (add-gjf)
$ find . -name "*.java" -exec /c/Users/koppor/Downloads/google-java-format_windows-x86-64.exe -r -a --skip-reflowing-long-strings --skip-javadoc-formatting "{}" \;

[koppor]

OMG - the windows binary of GJF behaves differently to the JAR -- google/google-java-format#1171