Fill Java CI gaps for Maven Central publication

.github/workflows/build.yaml

@@ -541,3 +541,23 @@ jobs:
           name: cudf_java_maven_repo
           path: ${{ runner.temp }}/maven-repo
           if-no-files-found: error
+
+  # Publish tagged release candidates to Maven Central via the Sonatype
+  # Central Publisher Portal.
+  java-publish:
+    needs: [java-gather]
+    if: ${{ github.ref_type == 'tag' && (inputs.build_type || 'branch') == 'branch' }}
+    permissions:
+      actions: read
+      contents: read
+    uses: rapidsai/shared-workflows/.github/workflows/maven-publish.yaml@release/26.08
+    secrets:
+      GPG_PRIVATE_KEY: ${{ secrets.GPG_PRIVATE_KEY }}
+      GPG_PASSPHRASE: ${{ secrets.GPG_PASSPHRASE }}
+      MAVEN_DEPLOY_TOKEN: ${{ secrets.MAVEN_DEPLOY_TOKEN }}
+    with:
+      publication-type: 'rc'
+      artifact-name: cudf_java_maven_repo
+      source-git-sha: ${{ inputs.sha || github.sha }}
+      # false = validate + drop (safe). true = stage PENDING for manual publish.
+      stage-for-maven-central-publish: true

java/ci/README.md

@@ -34,12 +34,15 @@ so plain `rm -rf` works.
 ### Step 2 - Package the cuDF Java JAR for one classifier
 
 ```bash
-./java/ci/build_cudf_java_jar.sh \
+GITHUB_REF=refs/heads/my-branch ./java/ci/build_cudf_java_jar.sh \
   --libcudf-dir /tmp/libcudf-cuda12 \
   --output-dir /tmp/jars \
   --cuda-version 12.9
 ```
 
+`GITHUB_REF` is required and selects release-tag vs SNAPSHOT versioning. See
+the versioning section below.
+
 This compiles the JNI layer against the static libcudf from Step 1 and emits
 the classifier JAR (e.g. `cudf-26.08.0-SNAPSHOT-cuda12.jar`), a
 classifier-independent sources jar and javadoc jar, and the POM into a
@@ -72,12 +75,14 @@ inside the container.
 
 This walks every subdirectory of `--jars-dir` (each subdir name IS the
 classifier), gathers the per-classifier JAR, one shared sources jar, one
-shared javadoc jar, and the shared POM, derives the artifact version from
-the JAR filenames (requiring a single unique version across subdirs), and
+shared javadoc jar, the shared POM, and seeds an unclassified primary JAR
+as a copy of the `cuda12` classifier. Derives the artifact version from
+the JAR filenames (requiring a single unique version across subdirs) and
 lays them out as:
 
 ```
 /tmp/maven-repo/ai/rapids/cudf/26.08.0-SNAPSHOT/
+    cudf-26.08.0-SNAPSHOT.jar
     cudf-26.08.0-SNAPSHOT-cuda12.jar
     cudf-26.08.0-SNAPSHOT-cuda13.jar
     cudf-26.08.0-SNAPSHOT-sources.jar
@@ -88,7 +93,25 @@ lays them out as:
 The set of classifiers is whatever subdirectories are present under
 `--jars-dir`. For a local `x86_64`-only run, populate `/tmp/jars/cuda12/`
 and `/tmp/jars/cuda13/`. For the full four-way release build, add
-`/tmp/jars/cuda12-arm64/` and `/tmp/jars/cuda13-arm64/`.
+`/tmp/jars/cuda12-arm64/` and `/tmp/jars/cuda13-arm64/`. The `cuda12`
+subdirectory is required because the unclassified primary JAR is copied from
+it, so an `aarch64`-only set of subdirectories is not a valid gather input.
+
+### Release Tag vs SNAPSHOT versioning
+
+Release tag CI runs (`GITHUB_REF=refs/tags/vYY.MM.PP`) produce release-versioned
+JARs (`cudf-26.08.0-*.jar`). All other runs produce `-SNAPSHOT`. Gated by
+[`rapids-is-release-build`](https://github.com/rapidsai/gha-tools/blob/main/tools/rapids-is-release-build).
+`GITHUB_REF` is required. `test_java_build_local.sh` defaults it to the current
+branch.
+
+To rehearse the release path locally:
+
+    GITHUB_REF=refs/tags/vYY.MM.PP ./java/ci/test_java_build_local.sh
+
+Rewrites `java/pom.xml` in place. Restore with `git checkout java/pom.xml`.
+
+### GitHub Actions
 
 In GitHub Actions (`.github/workflows/build.yaml`), the `java-build` matrix job
 runs Steps 1-2 per (CUDA x arch) entry and uploads each classifier subdir as a

java/ci/assemble_maven_repo.sh

@@ -166,12 +166,26 @@ if [[ -z "${FIRST_VERSION}" ]]; then
   exit 1
 fi
 
+DEST_DIR="${OUTPUT_DIR}/${GROUP_PATH}/${ARTIFACT_ID}/${FIRST_VERSION}"
+
+# Seed the unclassified primary from cuda12. Maven Central serves this to
+# consumers depending on ai.rapids:cudf without a <classifier>.
+PRIMARY_SOURCE="${DEST_DIR}/cudf-${FIRST_VERSION}-cuda12.jar"
+if [[ ! -f "${PRIMARY_SOURCE}" ]]; then
+  echo "Error: ${PRIMARY_SOURCE} missing." >&2
+  exit 1
+fi
+UNCLASSIFIED="${DEST_DIR}/cudf-${FIRST_VERSION}.jar"
+if [[ ! -f "${UNCLASSIFIED}" ]]; then
+  cp -f "${PRIMARY_SOURCE}" "${UNCLASSIFIED}"
+  echo "  + cudf-${FIRST_VERSION}.jar (unclassified primary, copy of cuda12)"
+fi
+
 # Sources and javadoc jars are classifier-independent (pure Java, no arch or
 # cuda variation). Every classifier subdir produces byte-equivalent copies;
 # pick the lexicographically first subdir's copy as canonical. Fail fast if
 # any subdir is missing either file - that indicates -Prelease or
 # -Pjavadoc-jdk17 did not activate for that classifier's build.
-DEST_DIR="${OUTPUT_DIR}/${GROUP_PATH}/${ARTIFACT_ID}/${FIRST_VERSION}"
 FIRST_CLASSIFIER_SUBDIR=""
 for subdir in "${JARS_DIR}"/*/; do
   if [[ -z ${FIRST_CLASSIFIER_SUBDIR} ]]; then

java/ci/build_cudf_java_jar.sh

@@ -121,6 +121,8 @@ require_arg --libcudf-dir  "${LIBCUDF_DIR}"
 require_arg --output-dir   "${OUTPUT_DIR}"
 require_arg --cuda-version "${CUDA_VERSION}"
 
+: "${GITHUB_REF:?GITHUB_REF must be set.}"
+
 if [[ ! -d ${LIBCUDF_DIR} ]]; then
   echo "Error: --libcudf-dir '${LIBCUDF_DIR}' does not exist."
   exit 1
@@ -194,6 +196,7 @@ DOCKER_ARGS=(
   --env PARALLEL_LEVEL="${PARALLEL_LEVEL}"
   --env HOST_UID="$(id -u)"
   --env HOST_GID="$(id -g)"
+  --env GITHUB_REF="${GITHUB_REF}"
 )
 
 if [[ -n ${CMAKE_CUDA_ARCHITECTURES} ]]; then

java/ci/build_cudf_java_jar_in_container.sh

@@ -107,6 +107,14 @@ fi
 cd "${REPO_ROOT}/java"
 
 CUDF_VERSION="$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout "${BUILD_ARG[@]}")"
+
+# Release tag builds strip -SNAPSHOT and rewrite the POM so packaged artifacts
+# carry the release version. Non-release builds keep -SNAPSHOT.
+if rapids-is-release-build; then
+  CUDF_VERSION="${CUDF_VERSION%-SNAPSHOT}"
+  mvn versions:set -DnewVersion="${CUDF_VERSION}" -DgenerateBackupPoms=false "${BUILD_ARG[@]}"
+fi
+
 rapids-logger "Packaging cuDF Java JAR version ${CUDF_VERSION} (libcudf: ${CUDF_INSTALL_DIR})"
 
 # The `clean` goal is intentionally omitted: /repo/java/target is a

java/ci/test_java_build_local.sh

@@ -143,6 +143,12 @@ record_step_end() {
 
 parse_args "$@"
 
+# Mirror GHA's GITHUB_REF locally so the container distinguishes SNAPSHOT from release-tag builds.
+if [[ -z "${GITHUB_REF:-}" ]]; then
+  GITHUB_REF="$(git -C "${SCRIPT_DIR}" symbolic-ref HEAD 2>/dev/null || true)"
+fi
+export GITHUB_REF
+
 require_arg --work-dir "${WORK_DIR}"
 
 mkdir -p "${WORK_DIR}"