diff --git a/.github/workflows/pr_build_linux.yml b/.github/workflows/pr_build_linux.yml
index ff69a2cc68..212b022200 100644
--- a/.github/workflows/pr_build_linux.yml
+++ b/.github/workflows/pr_build_linux.yml
@@ -48,10 +48,9 @@ jobs:
 
   # Fast syntactic-only scalafix check. Parses sources without compiling, so it
   # surfaces version-independent style issues (e.g. RedundantSyntax) in seconds,
-  # long before the lint-java matrix finishes its ~3.5 min build. It also scans
-  # the spark-4.1 / spark-4.2 sources that lint-java skips (those profiles can't
-  # run -Psemanticdb yet), so it is the only gate covering them. The full rule
-  # set, including the semantic rules, still runs in lint-java.
+  # long before lint-java finishes its ~3.5 min build. It is also the only gate
+  # covering the Spark profiles lint-java skips (3.4, 4.1, 4.2); see the
+  # lint-java header below for the rationale on those skips.
   scalafix-syntactic:
     name: Lint Scala (syntactic)
     runs-on: ubuntu-24.04
@@ -72,6 +71,14 @@ jobs:
             --exclude '**/target/**' \
             spark
 
+  # Semantic scalafix + prettier + working-tree check. The matrix is kept small:
+  # one row on the latest supported Spark/JDK (4.0 / JDK 21), plus one row on
+  # Spark 3.5 so the version-specific spark-3.x / spark-3.5 shim source dirs
+  # get semantic coverage too. 4.0 is the latest Spark that can currently run
+  # -Psemanticdb: semanticdb-scalac for the Scala 2.13.17 / 2.13.18 patch
+  # versions used by spark-4.1 / spark-4.2 has not been published yet. JDK 21
+  # is the newest JDK in the supported test matrix. Cross-version syntactic
+  # coverage is provided by scalafix-syntactic above.
   lint-java:
     needs: lint
     name: Lint Java (${{ matrix.profile.name }})
@@ -79,26 +86,16 @@ jobs:
     container:
       image: amd64/rust
       env:
-        JAVA_TOOL_OPTIONS: ${{ (matrix.profile.java_version == '17' || matrix.profile.java_version == '21') && '--add-exports=java.base/sun.nio.ch=ALL-UNNAMED --add-exports=java.base/sun.util.calendar=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED' || '' }}
+        JAVA_TOOL_OPTIONS: "--add-exports=java.base/sun.nio.ch=ALL-UNNAMED --add-exports=java.base/sun.util.calendar=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED"
     strategy:
       matrix:
         profile:
-          - name: "Spark 3.4, JDK 11, Scala 2.12"
-            java_version: "11"
-            maven_opts: "-Pspark-3.4 -Pscala-2.12"
           - name: "Spark 3.5, JDK 17, Scala 2.12"
             java_version: "17"
             maven_opts: "-Pspark-3.5 -Pscala-2.12"
-          - name: "Spark 4.0, JDK 17"
-            java_version: "17"
-            maven_opts: "-Pspark-4.0"
           - name: "Spark 4.0, JDK 21"
             java_version: "21"
             maven_opts: "-Pspark-4.0"
-          # Spark 4.1 and 4.2 are intentionally absent: the lint job invokes -Psemanticdb,
-          # but semanticdb-scalac for those Scala patch versions (2.13.17 / 2.13.18) is not
-          # yet published, so we cannot currently run scalafix against the spark-4.1 or
-          # spark-4.2 profiles.
       fail-fast: false
     steps:
       - uses: actions/checkout@v7
@@ -115,8 +112,9 @@ jobs:
           path: |
             ~/.m2/repository
             /root/.m2/repository
-          key: ${{ runner.os }}-java-maven-${{ hashFiles('**/pom.xml') }}-lint
+          key: ${{ runner.os }}-java-maven-${{ hashFiles('**/pom.xml') }}-lint-${{ matrix.profile.java_version }}
           restore-keys: |
+            ${{ runner.os }}-java-maven-${{ hashFiles('**/pom.xml') }}-lint-
             ${{ runner.os }}-java-maven-
 
       - name: Run scalafix check
@@ -124,30 +122,34 @@ jobs:
           ./mvnw -B package -DskipTests scalafix:scalafix -Dscalafix.mode=CHECK -Psemanticdb ${{ matrix.profile.maven_opts }}
 
       - name: Setup Node.js
+        if: matrix.profile.java_version == '21'
         uses: actions/setup-node@v7
         with:
           node-version: '24'
 
       - name: Install prettier
+        if: matrix.profile.java_version == '21'
         run: |
           npm install -g prettier
 
       - name: Run prettier
+        if: matrix.profile.java_version == '21'
         run: |
           npx prettier "**/*.md" --write
 
       - name: Mark workspace as safe for git
+        if: matrix.profile.java_version == '21'
         run: |
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
 
       - name: Check for any local git changes (such as generated docs)
+        if: matrix.profile.java_version == '21'
         run: |
           ./dev/ci/check-working-tree-clean.sh
 
   # Compile-only verification for Spark 4.1. Tests are intentionally skipped: the spark-4.1
   # profile is currently a build target only, and several runtime/test failures are tracked
-  # in follow-up PRs. Excluded from lint-java because semanticdb-scalac_2.13.17 is not yet
-  # published and the lint job activates -Psemanticdb.
+  # in follow-up PRs. See lint-java above for why Spark 4.1 is not linted.
   build-spark-4-1:
     needs: lint
     name: Build Spark 4.1, JDK 17