From 26319ca50f820923cbbe04ebcf002eed8cbd4398 Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 13:29:49 -0400
Subject: [PATCH 1/7] update generate_showcase.sh to use librarian

---
 java-showcase/scripts/generate_showcase.sh | 84 ++++++++--------------
 1 file changed, 31 insertions(+), 53 deletions(-)

diff --git a/java-showcase/scripts/generate_showcase.sh b/java-showcase/scripts/generate_showcase.sh
index 84e7f31f8570..9bcebc74655b 100755
--- a/java-showcase/scripts/generate_showcase.sh
+++ b/java-showcase/scripts/generate_showcase.sh
@@ -1,6 +1,5 @@
 #!/bin/bash
-# Generates the showcase library using the docker image, which is built
-# from the current state of the repo in order to test local changes.
+# Generates the showcase library using librarian.
 set -ex
 
 echo "******** Generating Showcase ********"
@@ -12,11 +11,8 @@ pushd "${ROOT_DIR}"
 source "${ROOT_DIR}/java-showcase/scripts/showcase_utilities.sh"
 
 cleanup() {
-  if [[ -z "${api_def_dir}" ]]; then
-    rm -rf "${api_def_dir}"
-  fi
-  if [[ -z "${showcase_def_dir}" ]]; then
-    rm -rf "${showcase_def_dir}"
+  if [[ -n "${generated_files_dir}" && "${replace}" != "true" ]]; then
+    rm -rf "${generated_files_dir}"
   fi
 }
 
@@ -39,58 +35,40 @@ if [ -z "${replace}" ]; then
   replace="false"
 fi
 
-
-# download api definitions from googleapis repository
-googleapis_commitish=$(grep googleapis_commitish generation_config.yaml | cut -d ":" -f 2 | xargs)
-api_def_dir=$(mktemp -d)
-git clone https://github.com/googleapis/googleapis.git "${api_def_dir}"
-
-pushd "${api_def_dir}"
-git checkout "${googleapis_commitish}"
-# for local setups, we avoid permission issues when the docker image
-# performs version-dependent operations.
-rm -rf ".git/"
-popd
-
-append_showcase_to_api_defs "${api_def_dir}"
-
-if [[ -f "image-id" ]]; then
-  echo "image already exists:"
-  cat image-id
+if command -v librarian &> /dev/null; then
+  LIBRARIAN_CMD="librarian"
 else
-  echo "building docker image"
-  DOCKER_BUILDKIT=1 docker build --file sdk-platform-java/.cloudbuild/library_generation/library_generation.Dockerfile --iidfile image-id .
+  LIBRARIAN_CMD="go run github.com/googleapis/librarian/cmd/librarian@latest"
 fi
 
 if [[ "${replace}" == "true" ]]; then
-  generated_files_dir="${ROOT_DIR}"
+  echo "generating showcase in place"
+  $LIBRARIAN_CMD generate showcase
 else
   export generated_files_dir=$(mktemp -d)
-  # here we store the generated library location for upstream scripts to use
-  # it.
+  echo "Temp generation directory: ${generated_files_dir}"
+  
+  # store the generated library location for verify.sh
   echo "${generated_files_dir}/java-showcase" > "${ROOT_DIR}/generated-showcase-location"
-  # we prepare the temp folder with the minimal setup to perform an incremental
-  # generation.
-  pushd "${ROOT_DIR}"
-  cp -r generation_config.yaml java-showcase/ versions.txt "${generated_files_dir}"
-  popd #ROOT_DIR
+  
+  # Symlink all contents of root directory except java-showcase and librarian.yaml
+  for item in "${ROOT_DIR}"/*; do
+    name=$(basename "$item")
+    if [[ "$name" != "java-showcase" && "$name" != "librarian.yaml" ]]; then
+      ln -s "$item" "${generated_files_dir}/${name}"
+    fi
+  done
+  
+  # Copy librarian.yaml and java-showcase to the temp directory
+  cp -r "${ROOT_DIR}/librarian.yaml" "${ROOT_DIR}/java-showcase" "${generated_files_dir}/"
+  
+  # Convert local paths in librarian.yaml to absolute paths
+  sed -i "s|local_path: sdk-platform-java|local_path: ${ROOT_DIR}/sdk-platform-java|g" "${generated_files_dir}/librarian.yaml"
+  
+  # Run librarian generate from the temp workspace
+  pushd "${generated_files_dir}"
+  $LIBRARIAN_CMD generate showcase
+  popd
 fi
 
-pushd sdk-platform-java
-GENERATOR_VERSION=$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout -pl gapic-generator-java)
-popd
-
-echo "generating showcase"
-workspace_name="/workspace"
-docker run \
-  --rm \
-  -u "$(id -u):$(id -g)" \
-  -v "${generated_files_dir}:${workspace_name}" \
-  -v "${api_def_dir}:${workspace_name}/googleapis" \
-  -e GENERATOR_VERSION="${GENERATOR_VERSION}" \
-  "$(cat image-id)" \
-  --generation-config-path="${workspace_name}/generation_config.yaml" \
-  --library-names="showcase" \
-  --api-definitions-path="${workspace_name}/googleapis"
-
-echo "generated showcase library in ${generated_files_dir}"
+echo "generated showcase library"

From 0379c8eb3513b5c5db591b9e1da9b1ab9e80b769 Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 13:56:09 -0400
Subject: [PATCH 2/7] update workflow and readme

---
 .github/workflows/showcase.yaml            | 23 +++++++++++++++++
 java-showcase/README.md                    | 30 ++++++++++++++++++----
 java-showcase/scripts/generate_showcase.sh |  3 +++
 3 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/showcase.yaml b/.github/workflows/showcase.yaml
index bb9901619966..cbef4e59e829 100644
--- a/.github/workflows/showcase.yaml
+++ b/.github/workflows/showcase.yaml
@@ -115,6 +115,29 @@ jobs:
         env:
           BUILD_SUBDIR: sdk-platform-java
           JOB_TYPE: install
+      - uses: actions/setup-go@v5
+        with:
+          go-version: 'stable'
+      - name: Install protoc
+        run: |
+          set -e
+          VERSION="33.2"
+          curl -fsSL --retry 5 --retry-delay 15 -o /tmp/protoc.zip "https://github.com/protocolbuffers/protobuf/releases/download/v$VERSION/protoc-$VERSION-linux-x86_64.zip"
+          cd /usr/local
+          sudo unzip -o /tmp/protoc.zip
+          protoc --version
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: 'pip'
+      - name: Install Librarian and tools
+        env:
+          PYTHONPATH: ${{ github.workspace }}/sdk-platform-java/hermetic_build/library_generation/owlbot
+        run: |
+          V=$(go run github.com/googleapis/librarian/cmd/librarian@latest config get version)
+          echo "Installing librarian version $V"
+          go install github.com/googleapis/librarian/cmd/librarian@$V
+          librarian install
       - name: Showcase golden tests
         working-directory: java-showcase
         run: |
diff --git a/java-showcase/README.md b/java-showcase/README.md
index 0c0fd75acd2f..a91a3e5cf8f6 100644
--- a/java-showcase/README.md
+++ b/java-showcase/README.md
@@ -7,7 +7,8 @@ the Showcase API which can communicate with a local Showcase server to perform i
 
 ## Requirements
 
-* Install [Go](https://go.dev) in your `PATH`.
+* Install [Go](https://go.dev) in your `PATH` (version 1.20 or later).
+* Install the [protoc](https://github.com/protocolbuffers/protobuf/releases) compiler in your `PATH`.
 
 ## Installing the Server
 
@@ -73,8 +74,26 @@ mvn verify -P enable-integration-tests
 
 ## Running the Golden tests
 
-**NOTE** This requires Docker to be installed in your machine.
-Open a new terminal window in the root project directory.
+This verify check compares the current checked-in files in `java-showcase` against a newly generated client.
+
+### Prerequisites (One-time Setup)
+Make sure you have **Go** and **protoc** installed and available in your `PATH` (see the [Requirements](#requirements) section), then run the following setup steps from the repository root:
+
+```shell
+# Setup and activate Python virtual environment
+python -m venv .venv
+source .venv/bin/activate
+
+# Configure pip for external sources
+pip config set global.extra-index-url https://pypi.org/simple
+
+# Install and configure Java tools (takes around 5 mins)
+V=$(go run github.com/googleapis/librarian/cmd/librarian@latest config get version)
+go run github.com/googleapis/librarian/cmd/librarian@${V} install
+```
+
+### Running the tests
+Once the prerequisites are installed and the virtual environment is activated, run:
 
 ```shell
 cd java-showcase
@@ -84,8 +103,9 @@ mvn verify -P enable-golden-tests
 
 ## Update the Golden Showcase Files
 
-**NOTE** This requires Docker to be installed in your machine.
-Open a new terminal window in the root project directory.
+To regenerate the showcase library files and update them in place:
+
+Make sure the Python virtual environment is activated, then run:
 
 ```shell
 # In repository's root directory
diff --git a/java-showcase/scripts/generate_showcase.sh b/java-showcase/scripts/generate_showcase.sh
index 9bcebc74655b..8eecdfeb16f6 100755
--- a/java-showcase/scripts/generate_showcase.sh
+++ b/java-showcase/scripts/generate_showcase.sh
@@ -7,6 +7,7 @@ echo "******** Generating Showcase ********"
 trap cleanup ERR
 
 readonly ROOT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )/../.."
+export PYTHONPATH="${ROOT_DIR}/sdk-platform-java/hermetic_build/library_generation/owlbot"
 pushd "${ROOT_DIR}"
 source "${ROOT_DIR}/java-showcase/scripts/showcase_utilities.sh"
 
@@ -44,6 +45,8 @@ fi
 if [[ "${replace}" == "true" ]]; then
   echo "generating showcase in place"
   $LIBRARIAN_CMD generate showcase
+  # Discard changes to root POM and BOM POM files modified by Librarian's Java post-processor
+  git restore "${ROOT_DIR}/pom.xml" "${ROOT_DIR}/gapic-libraries-bom/pom.xml" || true
 else
   export generated_files_dir=$(mktemp -d)
   echo "Temp generation directory: ${generated_files_dir}"

From accd37133c51ab7ef2651ff7fe63396d10b94a0f Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 14:47:34 -0400
Subject: [PATCH 3/7] simplify scripts by removing flag

---
 java-showcase/pom.xml                      |  2 -
 java-showcase/scripts/generate_showcase.sh | 72 +++-------------------
 java-showcase/scripts/verify.sh            | 21 +++----
 3 files changed, 17 insertions(+), 78 deletions(-)

diff --git a/java-showcase/pom.xml b/java-showcase/pom.xml
index c6a9a0352f57..73ba577a62d1 100644
--- a/java-showcase/pom.xml
+++ b/java-showcase/pom.xml
@@ -251,8 +251,6 @@
                   <executable>bash</executable>
                   <arguments>
                     <argument>scripts/generate_showcase.sh</argument>
-                    <argument>--replace</argument>
-                    <argument>true</argument>
                   </arguments>
                 </configuration>
               </execution>
diff --git a/java-showcase/scripts/generate_showcase.sh b/java-showcase/scripts/generate_showcase.sh
index 8eecdfeb16f6..6b3d962c79b4 100755
--- a/java-showcase/scripts/generate_showcase.sh
+++ b/java-showcase/scripts/generate_showcase.sh
@@ -4,74 +4,16 @@ set -ex
 
 echo "******** Generating Showcase ********"
 
-trap cleanup ERR
-
 readonly ROOT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )/../.."
+# Export PYTHONPATH so that owlbot.py scripts run by Librarian
+# can resolve local synthtool under the hermetic build directory.
 export PYTHONPATH="${ROOT_DIR}/sdk-platform-java/hermetic_build/library_generation/owlbot"
-pushd "${ROOT_DIR}"
-source "${ROOT_DIR}/java-showcase/scripts/showcase_utilities.sh"
-
-cleanup() {
-  if [[ -n "${generated_files_dir}" && "${replace}" != "true" ]]; then
-    rm -rf "${generated_files_dir}"
-  fi
-}
-
-while [[ $# -gt 0 ]]; do
-key="$1"
-case "${key}" in
-  --replace)
-    replace="$2"
-    shift
-    ;;
-  *)
-    echo "Invalid option: [$1]"
-    exit 1
-    ;;
-esac
-shift
-done
-
-if [ -z "${replace}" ]; then
-  replace="false"
-fi
+cd "${ROOT_DIR}"
 
-if command -v librarian &> /dev/null; then
-  LIBRARIAN_CMD="librarian"
-else
-  LIBRARIAN_CMD="go run github.com/googleapis/librarian/cmd/librarian@latest"
-fi
+readonly LIBRARIAN_VER=$(go run github.com/googleapis/librarian/cmd/librarian@latest config get version)
+readonly LIBRARIAN_CMD="go run github.com/googleapis/librarian/cmd/librarian@${LIBRARIAN_VER}"
 
-if [[ "${replace}" == "true" ]]; then
-  echo "generating showcase in place"
-  $LIBRARIAN_CMD generate showcase
-  # Discard changes to root POM and BOM POM files modified by Librarian's Java post-processor
-  git restore "${ROOT_DIR}/pom.xml" "${ROOT_DIR}/gapic-libraries-bom/pom.xml" || true
-else
-  export generated_files_dir=$(mktemp -d)
-  echo "Temp generation directory: ${generated_files_dir}"
-  
-  # store the generated library location for verify.sh
-  echo "${generated_files_dir}/java-showcase" > "${ROOT_DIR}/generated-showcase-location"
-  
-  # Symlink all contents of root directory except java-showcase and librarian.yaml
-  for item in "${ROOT_DIR}"/*; do
-    name=$(basename "$item")
-    if [[ "$name" != "java-showcase" && "$name" != "librarian.yaml" ]]; then
-      ln -s "$item" "${generated_files_dir}/${name}"
-    fi
-  done
-  
-  # Copy librarian.yaml and java-showcase to the temp directory
-  cp -r "${ROOT_DIR}/librarian.yaml" "${ROOT_DIR}/java-showcase" "${generated_files_dir}/"
-  
-  # Convert local paths in librarian.yaml to absolute paths
-  sed -i "s|local_path: sdk-platform-java|local_path: ${ROOT_DIR}/sdk-platform-java|g" "${generated_files_dir}/librarian.yaml"
-  
-  # Run librarian generate from the temp workspace
-  pushd "${generated_files_dir}"
-  $LIBRARIAN_CMD generate showcase
-  popd
-fi
+echo "generating showcase in place"
+$LIBRARIAN_CMD generate showcase
 
 echo "generated showcase library"
diff --git a/java-showcase/scripts/verify.sh b/java-showcase/scripts/verify.sh
index 4a75ceb6e777..f21f8d5a4f68 100755
--- a/java-showcase/scripts/verify.sh
+++ b/java-showcase/scripts/verify.sh
@@ -1,21 +1,20 @@
 #!/bin/sh
-# This script generates showcase in a temporary/untracked folder and compares
-# its contents with the actual showcase libraries. 
+# This script generates showcase in place and checks for git diffs to verify.
 
 echo "******** Verifying Showcase ********"
 
 set -oxe
 readonly SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 readonly ROOT_DIR="${SCRIPT_DIR}/../.."
-source "${SCRIPT_DIR}/showcase_utilities.sh"
 readonly SHOWCASE_DIR="${SCRIPT_DIR}/.."
+readonly GENERATED_DIRS="${SHOWCASE_DIR}/gapic-showcase/src/main ${SHOWCASE_DIR}/grpc-gapic-showcase-v1beta1/src/main ${SHOWCASE_DIR}/proto-gapic-showcase-v1beta1/src/main"
 
-# generate sources
-bash "${SCRIPT_DIR}/generate_showcase.sh" --replace "false"
+# generate sources in place
+bash "${SCRIPT_DIR}/generate_showcase.sh"
 
-generated_library_location=$(cat "${ROOT_DIR}/generated-showcase-location")
-
-# compare library
-diff -ru "${SHOWCASE_DIR}/" "${generated_library_location}"
-
-cleanup $SCRIPT_DIR
+# check if there are changes in generated directories
+if [ -n "$(git status --porcelain ${GENERATED_DIRS})" ]; then
+  git diff ${GENERATED_DIRS}
+  echo "Error: Showcase generated files are out of sync. Please run 'mvn compile -P update' inside java-showcase to update them."
+  exit 1
+fi

From a77c2ebe74937050755211469b8d9c254d5a9320 Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 15:22:14 -0400
Subject: [PATCH 4/7] fix verify.sh

---
 java-showcase/scripts/verify.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/java-showcase/scripts/verify.sh b/java-showcase/scripts/verify.sh
index f21f8d5a4f68..cda360c98e3b 100755
--- a/java-showcase/scripts/verify.sh
+++ b/java-showcase/scripts/verify.sh
@@ -1,9 +1,9 @@
-#!/bin/sh
+#!/bin/bash
 # This script generates showcase in place and checks for git diffs to verify.
 
 echo "******** Verifying Showcase ********"
 
-set -oxe
+set -ex
 readonly SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 readonly ROOT_DIR="${SCRIPT_DIR}/../.."
 readonly SHOWCASE_DIR="${SCRIPT_DIR}/.."

From f497c9e114ea81cca7e131d9903e661cceebd929 Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 16:49:44 -0400
Subject: [PATCH 5/7] use java 17 for code generation

---
 .github/workflows/showcase.yaml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/.github/workflows/showcase.yaml b/.github/workflows/showcase.yaml
index cbef4e59e829..ba670a1fa5cf 100644
--- a/.github/workflows/showcase.yaml
+++ b/.github/workflows/showcase.yaml
@@ -138,6 +138,11 @@ jobs:
           echo "Installing librarian version $V"
           go install github.com/googleapis/librarian/cmd/librarian@$V
           librarian install
+      - name: Setup Java 17 for Golden Tests
+        uses: actions/setup-java@v4
+        with:
+          java-version: 17
+          distribution: temurin
       - name: Showcase golden tests
         working-directory: java-showcase
         run: |
@@ -145,6 +150,11 @@ jobs:
             -P enable-golden-tests \
             --batch-mode \
             --no-transfer-progress
+      - name: Restore Matrix Java
+        uses: actions/setup-java@v4
+        with:
+          java-version: ${{ matrix.java }}
+          distribution: temurin
       - name: Parse showcase version
         working-directory: java-showcase/gapic-showcase
         run: echo "SHOWCASE_VERSION=$(mvn help:evaluate -Dexpression=gapic-showcase.version -q -DforceStdout)" >> "$GITHUB_ENV"

From 81b12c67dfb6d134fa9327e9be194b93a2847857 Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 16:55:30 -0400
Subject: [PATCH 6/7] restrict pip config to active virtual environment

---
 java-showcase/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/java-showcase/README.md b/java-showcase/README.md
index a91a3e5cf8f6..3edf3fd28e84 100644
--- a/java-showcase/README.md
+++ b/java-showcase/README.md
@@ -85,7 +85,7 @@ python -m venv .venv
 source .venv/bin/activate
 
 # Configure pip for external sources
-pip config set global.extra-index-url https://pypi.org/simple
+pip config --venv set global.extra-index-url https://pypi.org/simple
 
 # Install and configure Java tools (takes around 5 mins)
 V=$(go run github.com/googleapis/librarian/cmd/librarian@latest config get version)

From a4e488e7bf0facb960745189c40f9e1803a53c4a Mon Sep 17 00:00:00 2001
From: Min Zhu <zhumin@google.com>
Date: Mon, 29 Jun 2026 17:20:30 -0400
Subject: [PATCH 7/7] check all java-showcase in test and clarify need clean
 git tree in README

---
 java-showcase/README.md         | 2 ++
 java-showcase/scripts/verify.sh | 8 +++-----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/java-showcase/README.md b/java-showcase/README.md
index 3edf3fd28e84..5c9d2b0b0f95 100644
--- a/java-showcase/README.md
+++ b/java-showcase/README.md
@@ -100,6 +100,8 @@ cd java-showcase
 mvn verify -P enable-golden-tests
 ```
 
+> [!IMPORTANT]
+> The golden tests run the generator and compare the entire `java-showcase` directory against the newly generated state using `git diff`. For these tests to pass, you must have a completely clean git tree within the `java-showcase` directory before running them. Any uncommitted changes or untracked files will cause the tests to fail.
 
 ## Update the Golden Showcase Files
 
diff --git a/java-showcase/scripts/verify.sh b/java-showcase/scripts/verify.sh
index cda360c98e3b..213b1de9165d 100755
--- a/java-showcase/scripts/verify.sh
+++ b/java-showcase/scripts/verify.sh
@@ -7,14 +7,12 @@ set -ex
 readonly SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 readonly ROOT_DIR="${SCRIPT_DIR}/../.."
 readonly SHOWCASE_DIR="${SCRIPT_DIR}/.."
-readonly GENERATED_DIRS="${SHOWCASE_DIR}/gapic-showcase/src/main ${SHOWCASE_DIR}/grpc-gapic-showcase-v1beta1/src/main ${SHOWCASE_DIR}/proto-gapic-showcase-v1beta1/src/main"
-
 # generate sources in place
 bash "${SCRIPT_DIR}/generate_showcase.sh"
 
-# check if there are changes in generated directories
-if [ -n "$(git status --porcelain ${GENERATED_DIRS})" ]; then
-  git diff ${GENERATED_DIRS}
+# check if there are changes in java-showcase directory
+if [ -n "$(git status --porcelain ${SHOWCASE_DIR})" ]; then
+  git diff ${SHOWCASE_DIR}
   echo "Error: Showcase generated files are out of sync. Please run 'mvn compile -P update' inside java-showcase to update them."
   exit 1
 fi