From 823205fbb7a00fcd611abe6bab5ebe3357ca868c Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 02:56:38 +0530
Subject: [PATCH 1/6] Add lint-changed task in Java workflow

---
 .github/workflows/java.yml | 21 +++++++++++++--
 bin/lint-changed-exercise  | 54 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 2 deletions(-)
 create mode 100644 bin/lint-changed-exercise

diff --git a/.github/workflows/java.yml b/.github/workflows/java.yml
index ef2f2017e..e5b689abc 100644
--- a/.github/workflows/java.yml
+++ b/.github/workflows/java.yml
@@ -25,8 +25,9 @@ jobs:
         run: ./gradlew compileStarterTestJava --continue
         working-directory: exercises
 
-  lint:
-    name: Lint Java files using Checkstyle
+  lint-all:
+    name: Lint all Java files using Checkstyle
+    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
@@ -39,6 +40,22 @@ jobs:
         run: ./gradlew check --exclude-task test --continue
         working-directory: exercises
 
+  lint-changed:
+    name: Lint changed Java exercises using Checkstyle
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
+        with:
+          fetch-depth: 0
+      - name: Set up JDK 21
+        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
+        with:
+          java-version: 21
+          distribution: "temurin"
+      - name: Lint changed exercises
+        run: bin/lint-changed-exercise
+
   test-all:
     name: Test all exercises using java-test-runner
     if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
diff --git a/bin/lint-changed-exercise b/bin/lint-changed-exercise
new file mode 100644
index 000000000..7fc6b96dc
--- /dev/null
+++ b/bin/lint-changed-exercise
@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Determine the base branch of the PR
+BASE_BRANCH=${GITHUB_BASE_REF:-main}
+
+# Fetch full history for proper diff
+git fetch origin "$BASE_BRANCH"
+
+# Compute merge base
+MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
+
+# Get changed files relative to merge base
+changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+
+# If any Gradle build file changed, run the full suite and exit
+if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
+  echo "Gradle build files changed, running full lint suite..."
+  cd exercises && ./gradlew check --exclude-task test --continue
+  exit 0
+fi
+
+# Extract unique exercise directories
+changed_exercises=$(echo "$changed_files" | \
+  grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
+  cut -d/ -f1-3 | sort -u)
+
+if [ -z "$changed_exercises" ]; then
+  echo "No relevant exercises changed, skipping linting."
+  exit 0
+fi
+
+# Print exercises
+echo "Changed exercises detected:"
+echo "$changed_exercises"
+echo "----------------------------------------"
+
+# Run lint checks
+exit_code=0
+for dir in $changed_exercises; do
+  slug=$(basename "$dir")
+
+  echo "========================================"
+  echo "=== Running checkstyle for $slug ==="
+  echo "========================================"
+
+  if [[ $dir == exercises/practice/* ]]; then
+    ./exercises/gradlew -p exercises ":practice:$slug:check" --exclude-task test || exit_code=1
+  elif [[ $dir == exercises/concept/* ]]; then
+    ./exercises/gradlew -p exercises ":concept:$slug:check" --exclude-task test || exit_code=1
+  fi
+done
+
+exit $exit_code

From e7630145b006bf07a8d16db51dc4e68895b60e67 Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 03:36:19 +0530
Subject: [PATCH 2/6] ci: implement build-changed strategy for targeted test
 compilation

---
 .github/workflows/java.yml | 19 +++++++++++++-
 bin/build-changed-exercise | 54 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100755 bin/build-changed-exercise

diff --git a/.github/workflows/java.yml b/.github/workflows/java.yml
index ef2f2017e..eb9393519 100644
--- a/.github/workflows/java.yml
+++ b/.github/workflows/java.yml
@@ -11,8 +11,9 @@ on:
   workflow_dispatch:
 
 jobs:
-  build:
+  build-all:
     name: Check if tests compile cleanly with starter sources
+    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
@@ -25,6 +26,22 @@ jobs:
         run: ./gradlew compileStarterTestJava --continue
         working-directory: exercises
 
+  build-changed:
+    name: Check if changed exercise tests compile cleanly with starter sources
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
+        with:
+          fetch-depth: 0
+      - name: Set up JDK 21
+        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
+        with:
+          java-version: 21
+          distribution: "temurin"
+      - name: Check if changed exercise tests compile cleanly
+        run: bin/build-changed-exercise
+
   lint:
     name: Lint Java files using Checkstyle
     runs-on: ubuntu-24.04
diff --git a/bin/build-changed-exercise b/bin/build-changed-exercise
new file mode 100755
index 000000000..ebb52a69e
--- /dev/null
+++ b/bin/build-changed-exercise
@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Determine the base branch of the PR
+BASE_BRANCH=${GITHUB_BASE_REF:-main}
+
+# Fetch full history for proper diff
+git fetch origin "$BASE_BRANCH"
+
+# Compute merge base
+MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
+
+# Get changed files relative to merge base
+changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+
+# If any Gradle build file changed, run the full suite and exit
+if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
+  echo "Gradle build files changed, running full build suite..."
+  cd exercises && ./gradlew compileStarterTestJava --continue
+  exit 0
+fi
+
+# Extract unique exercise directories
+changed_exercises=$(echo "$changed_files" | \
+  grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
+  cut -d/ -f1-3 | sort -u || true)
+
+if [ -z "$changed_exercises" ]; then
+  echo "No relevant exercises changed, skipping compile checks."
+  exit 0
+fi
+
+# Print exercises
+echo "Changed exercises detected:"
+echo "$changed_exercises"
+echo "----------------------------------------"
+
+# Run build compile checks
+exit_code=0
+for dir in $changed_exercises; do
+  slug=$(basename "$dir")
+
+  echo "========================================"
+  echo "=== Running compileStarterTestJava for $slug ==="
+  echo "========================================"
+
+  if [[ $dir == exercises/practice/* ]]; then
+    ./exercises/gradlew -p exercises ":practice:$slug:compileStarterTestJava" || exit_code=1
+  elif [[ $dir == exercises/concept/* ]]; then
+    ./exercises/gradlew -p exercises ":concept:$slug:compileStarterTestJava" || exit_code=1
+  fi
+done
+
+exit $exit_code

From 116ea887e26ca4ba1a02a0fc3ee030f5f68312ba Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 22:53:32 +0530
Subject: [PATCH 3/6] Combine common logic

---
 bin/build-changed-exercise | 25 ++++---------------------
 bin/common.sh              | 36 ++++++++++++++++++++++++++++++++++++
 bin/lint-changed-exercise  | 25 ++++---------------------
 bin/test-changed-exercise  | 25 ++++---------------------
 4 files changed, 48 insertions(+), 63 deletions(-)
 create mode 100644 bin/common.sh

diff --git a/bin/build-changed-exercise b/bin/build-changed-exercise
index ebb52a69e..9238b6744 100755
--- a/bin/build-changed-exercise
+++ b/bin/build-changed-exercise
@@ -1,29 +1,12 @@
 #!/usr/bin/env bash
 set -eo pipefail
 
-# Determine the base branch of the PR
-BASE_BRANCH=${GITHUB_BASE_REF:-main}
-
-# Fetch full history for proper diff
-git fetch origin "$BASE_BRANCH"
-
-# Compute merge base
-MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
-
-# Get changed files relative to merge base
-changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+source "$(dirname "$0")/common.sh"
 
 # If any Gradle build file changed, run the full suite and exit
-if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
-  echo "Gradle build files changed, running full build suite..."
-  cd exercises && ./gradlew compileStarterTestJava --continue
-  exit 0
-fi
-
-# Extract unique exercise directories
-changed_exercises=$(echo "$changed_files" | \
-  grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
-  cut -d/ -f1-3 | sort -u || true)
+check_gradle_changes \
+  "cd exercises && ./gradlew compileStarterTestJava --continue" \
+  "Gradle build files changed, running full build suite..."
 
 if [ -z "$changed_exercises" ]; then
   echo "No relevant exercises changed, skipping compile checks."
diff --git a/bin/common.sh b/bin/common.sh
new file mode 100644
index 000000000..005d275e0
--- /dev/null
+++ b/bin/common.sh
@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Determine the base branch of the PR
+BASE_BRANCH=${GITHUB_BASE_REF:-main}
+
+# Fetch full history for proper diff
+git fetch origin "$BASE_BRANCH"
+
+# Compute merge base
+MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
+
+# Get changed files relative to merge base
+changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+
+# Function to check if Gradle build files changed and run a command
+check_gradle_changes() {
+  local command="$1"
+  local message="$2"
+  
+  if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
+    echo "$message"
+    eval "$command"
+    exit 0
+  fi
+}
+
+# Extract unique exercise directories
+get_changed_exercises() {
+  echo "$changed_files" | \
+    grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
+    cut -d/ -f1-3 | sort -u || true
+}
+
+# Variable for reuse
+changed_exercises=$(get_changed_exercises)
diff --git a/bin/lint-changed-exercise b/bin/lint-changed-exercise
index 7fc6b96dc..bbb6efc26 100644
--- a/bin/lint-changed-exercise
+++ b/bin/lint-changed-exercise
@@ -1,29 +1,12 @@
 #!/usr/bin/env bash
 set -eo pipefail
 
-# Determine the base branch of the PR
-BASE_BRANCH=${GITHUB_BASE_REF:-main}
-
-# Fetch full history for proper diff
-git fetch origin "$BASE_BRANCH"
-
-# Compute merge base
-MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
-
-# Get changed files relative to merge base
-changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+source "$(dirname "$0")/common.sh"
 
 # If any Gradle build file changed, run the full suite and exit
-if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
-  echo "Gradle build files changed, running full lint suite..."
-  cd exercises && ./gradlew check --exclude-task test --continue
-  exit 0
-fi
-
-# Extract unique exercise directories
-changed_exercises=$(echo "$changed_files" | \
-  grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
-  cut -d/ -f1-3 | sort -u)
+check_gradle_changes \
+  "cd exercises && ./gradlew check --exclude-task test --continue" \
+  "Gradle build files changed, running full lint suite..."
 
 if [ -z "$changed_exercises" ]; then
   echo "No relevant exercises changed, skipping linting."
diff --git a/bin/test-changed-exercise b/bin/test-changed-exercise
index b18a488e8..4e71b25a4 100755
--- a/bin/test-changed-exercise
+++ b/bin/test-changed-exercise
@@ -1,29 +1,12 @@
 #!/usr/bin/env bash
 set -eo pipefail
 
-# Determine the base branch of the PR
-BASE_BRANCH=${GITHUB_BASE_REF:-main}
-
-# Fetch full history for proper diff
-git fetch origin "$BASE_BRANCH"
-
-# Compute merge base
-MERGE_BASE=$(git merge-base HEAD origin/"$BASE_BRANCH")
-
-# Get changed files relative to merge base
-changed_files=$(git diff --name-only "$MERGE_BASE" HEAD)
+source "$(dirname "$0")/common.sh"
 
 # If any Gradle build file changed, run the full suite and exit
-if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
-  echo "Gradle build files changed, running full test suite..."
-  ./bin/test-with-test-runner
-  exit 0
-fi
-
-# Extract unique exercise directories
-changed_exercises=$(echo "$changed_files" | \
-  grep -E '^exercises/(practice|concept)/[^/]+/.+\.java$' | \
-  cut -d/ -f1-3 | sort -u)
+check_gradle_changes \
+  "./bin/test-with-test-runner" \
+  "Gradle build files changed, running full test suite..."
 
 if [ -z "$changed_exercises" ]; then
   echo "No relevant exercises changed, skipping tests."

From cf51d14812ad9f3dd7346266bff600c662a51885 Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 22:57:43 +0530
Subject: [PATCH 4/6] Fix script permissions in Git index

---
 bin/common.sh             | 0
 bin/lint-changed-exercise | 0
 2 files changed, 0 insertions(+), 0 deletions(-)
 mode change 100644 => 100755 bin/common.sh
 mode change 100644 => 100755 bin/lint-changed-exercise

diff --git a/bin/common.sh b/bin/common.sh
old mode 100644
new mode 100755
diff --git a/bin/lint-changed-exercise b/bin/lint-changed-exercise
old mode 100644
new mode 100755

From 2b5b66a9b36fdb7c1ae8f3590f5cc7bf63c4a83a Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 23:20:40 +0530
Subject: [PATCH 5/6] Update Java version to 25 in CI

---
 .github/workflows/java.yml | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/java.yml b/.github/workflows/java.yml
index ab88e39c8..2e43b527a 100644
--- a/.github/workflows/java.yml
+++ b/.github/workflows/java.yml
@@ -17,10 +17,10 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
         with:
-          java-version: 21
+          java-version: 25
           distribution: "temurin"
       - name: Check if tests compile cleanly with starter sources
         run: ./gradlew compileStarterTestJava --continue
@@ -34,10 +34,10 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
         with:
           fetch-depth: 0
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
         with:
-          java-version: 21
+          java-version: 25
           distribution: "temurin"
       - name: Check if changed exercise tests compile cleanly
         run: bin/build-changed-exercise
@@ -48,10 +48,10 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
         with:
-          java-version: 21
+          java-version: 25
           distribution: "temurin"
       - name: Run checkstyle
         run: ./gradlew check --exclude-task test --continue
@@ -65,10 +65,10 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
         with:
           fetch-depth: 0
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654
         with:
-          java-version: 21
+          java-version: 25
           distribution: "temurin"
       - name: Lint changed exercises
         run: bin/lint-changed-exercise

From 8352d6f239420445a7146e10a8563c1d9b7e72ef Mon Sep 17 00:00:00 2001
From: Jagdish Prajapati <jagadishdrp@gmail.com>
Date: Sat, 9 May 2026 23:31:59 +0530
Subject: [PATCH 6/6] Add gradle wrapper files in detection

---
 bin/common.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bin/common.sh b/bin/common.sh
index 005d275e0..9a84eb6d8 100755
--- a/bin/common.sh
+++ b/bin/common.sh
@@ -18,7 +18,7 @@ check_gradle_changes() {
   local command="$1"
   local message="$2"
   
-  if echo "$changed_files" | grep -qE '\.(gradle|gradlew|bat)$|settings\.gradle'; then
+  if echo "$changed_files" | grep -qE '(\.gradle|gradlew|\.bat|settings\.gradle|gradle-wrapper\.(properties|jar))$'; then
     echo "$message"
     eval "$command"
     exit 0