build: upgrade google-java-format and restore strict Spotless validation (#7091)

# Description of Changes

- Upgraded google-java-format from 1.28.0 to 1.35.0.
- Removed the broad `suppressLintsFor` workaround for the
`google-java-format` step.
- Ensured the shared `gradle/spotless.gradle` configuration is
recognized by the relevant CI path filters and repository automation.
- Kept the shared formatter configuration available to all backend
modules.
- Verified that google-java-format 1.35.0 runs successfully on JDK 25
for the Common, Core, and SaaS modules.
- Confirmed that the previous claim about a general Guava 32.x crash on
JDK 24/25 no longer justifies suppressing all formatter lint failures.

### Verification

Verified with Temurin JDK 25.0.3 and google-java-format 1.35.0. The
formatter still depends on Guava 32.1.3-jre, and no `suppressLintsFor`
configuration is present.

```bash
./gradlew \
  :common:spotlessJavaCheck \
  :stirling-pdf:spotlessJavaCheck \
  --rerun-tasks
```

Result:

```text
> Task :common:spotlessJava
> Task :common:spotlessJavaCheck
> Task :stirling-pdf:spotlessJava
> Task :stirling-pdf:spotlessJavaCheck

BUILD SUCCESSFUL in 26s
4 actionable tasks: 4 executed
```

Using `--rerun-tasks` ensured that the formatter was executed and that
the result did not come from the Gradle task cache.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/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)
- [ ] I have performed a self-review of my own code
- [ ] 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)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### 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)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/config/.files.yaml

@@ -9,6 +9,7 @@ ci: &ci
 build: &build
   - *ci
   - build.gradle
+  - gradle/spotless.gradle
   - app/(common|core|proprietary|saas)/build.gradle
   - Taskfile.yml
   - .taskfiles/backend.yml
@@ -155,4 +156,5 @@ proprietary: &proprietary
   - configs/settings.yml.template
   - build.gradle
   - app/proprietary/build.gradle
+  - gradle/spotless.gradle
   - .github/workflows/build-enterprise.yml

.github/workflows/sync_files_v2.yml

@@ -10,6 +10,7 @@ on:
       - "app/common/build.gradle"
       - "app/core/build.gradle"
       - "app/proprietary/build.gradle"
+      - "gradle/spotless.gradle"
       - "README.md"
       - "frontend/editor/public/locales/*/translation.toml"
       - "app/core/src/main/resources/static/3rdPartyLicenses.json"

app/common/build.gradle

@@ -2,32 +2,6 @@
 bootRun {
     enabled = false
 }
-spotless {
-    java {
-        target 'src/**/java/**/*.java'
-        targetExclude 'src/main/java/org/apache/**'
-        googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
-        // google-java-format 1.28.0 bundles Guava 32.x which crashes Spotless lint on JDK 24/25
-        suppressLintsFor { setStep('google-java-format') }
-
-        importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    yaml {
-        target '**/*.yml', '**/*.yaml'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    format 'gradle', {
-        target '**/gradle/*.gradle', '**/*.gradle'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-}
 dependencies {
     api "com.google.guava:guava:${guavaVersion}"
     api 'org.springframework.boot:spring-boot-starter-webmvc'

app/core/build.gradle

@@ -9,35 +9,6 @@ configurations {
     }
 }
 
-spotless {
-    java {
-        target 'src/**/java/**/*.java'
-        targetExclude 'src/main/resources/static/**', 'src/main/java/org/apache/**'
-        googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
-        // google-java-format 1.28.0 bundles Guava 32.x which crashes Spotless lint on JDK 24/25
-        suppressLintsFor { setStep('google-java-format') }
-
-        importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    yaml {
-        target '**/*.yml', '**/*.yaml'
-        targetExclude 'src/main/resources/static/**'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    format 'gradle', {
-        target '**/gradle/*.gradle', '**/*.gradle'
-        targetExclude 'src/main/resources/static/**'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-}
-
 dependencies {
     if (!gradle.ext.disableAdditional) {
         implementation project(':proprietary')

app/proprietary/build.gradle

@@ -6,33 +6,6 @@ repositories {
 bootRun {
     enabled = false
 }
-
-spotless {
-        java {
-        target 'src/**/java/**/*.java'
-        targetExclude 'src/main/java/org/apache/**'
-        googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
-        // google-java-format 1.28.0 bundles Guava 32.x which crashes Spotless lint on JDK 24/25
-        suppressLintsFor { setStep('google-java-format') }
-
-        importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    yaml {
-        target '**/*.yml', '**/*.yaml'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    format 'gradle', {
-        target '**/gradle/*.gradle', '**/*.gradle'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-}
 dependencies {
     implementation project(':common')
     api "com.google.guava:guava:${guavaVersion}"

app/saas/build.gradle

@@ -2,32 +2,6 @@ bootRun {
     enabled = false
 }
 
-spotless {
-    java {
-        target 'src/**/java/**/*.java'
-        targetExclude 'src/main/java/org/apache/**'
-        googleJavaFormat(googleJavaFormatVersion).aosp().reorderImports(false)
-        suppressLintsFor { setStep('google-java-format') }
-
-        importOrder("java", "javax", "org", "com", "net", "io", "jakarta", "lombok", "me", "stirling")
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    yaml {
-        target '**/*.yml', '**/*.yaml'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-    format 'gradle', {
-        target '**/gradle/*.gradle', '**/*.gradle'
-        trimTrailingWhitespace()
-        leadingTabsToSpaces()
-        endWithNewline()
-    }
-}
-
 dependencies {
     implementation project(':common')
     implementation project(':proprietary')

build.gradle

@@ -28,7 +28,7 @@ ext {
     springSecuritySamlVersion = "7.0.5"
     openSamlVersion = "5.2.1"
     commonmarkVersion = "0.28.0"
-    googleJavaFormatVersion = "1.28.0"
+    googleJavaFormatVersion = "1.35.0"
     logback = "1.5.32"
     commonsIoVersion = "2.22.0"
     commonsLang3 = "3.20.0"
@@ -37,7 +37,7 @@ ext {
     gsonVersion = "2.14.0"
     guavaVersion = "33.6.0-jre"
     jinjavaVersion = "2.8.3"
-    jackson2Version = "2.21.2"
+    jackson2Version = "2.21.4"
     bucket4jVersion = "8.19.0"
     archunitVersion = "1.4.2"
     batikVersion = "1.19"
@@ -171,6 +171,7 @@ subprojects {
     apply plugin: 'org.springframework.boot'
     apply plugin: 'io.spring.dependency-management'
     apply plugin: 'jacoco'
+    apply from: rootProject.file('gradle/spotless.gradle')
 
     java {
         sourceCompatibility = JavaVersion.VERSION_25

gradle/spotless.gradle

@@ -0,0 +1,37 @@
+spotless {
+    java {
+        target 'src/**/java/**/*.java'
+        if (project.name == 'stirling-pdf') {
+            targetExclude 'src/main/resources/static/**', 'src/main/java/org/apache/**'
+        } else {
+            targetExclude 'src/main/java/org/apache/**'
+        }
+
+        // licenseHeaderFile(file('config/license-header.txt')).updateYearWithLatest(true).yearStringFormat('%s')
+        removeUnusedImports()
+        googleJavaFormat(rootProject.ext.googleJavaFormatVersion).aosp().reorderImports(false)
+
+        importOrder('java', 'javax', 'org', 'com', 'net', 'io', 'jakarta', 'lombok', 'me', 'stirling')
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+    yaml {
+        target '**/*.yml', '**/*.yaml'
+        if (project.name == 'stirling-pdf') {
+            targetExclude 'src/main/resources/static/**'
+        }
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+    format 'gradle', {
+        target '**/gradle/*.gradle', '**/*.gradle'
+        if (project.name == 'stirling-pdf') {
+            targetExclude 'src/main/resources/static/**'
+        }
+        trimTrailingWhitespace()
+        leadingTabsToSpaces()
+        endWithNewline()
+    }
+}