Fix #5953: [java] PoC: Add rewrite support for errorprone.refasterrules

Author: Vincent Potucek

.github/workflows/build.yml

@@ -36,7 +36,7 @@ jobs:
           enableCrossOsArchive: true
       - name: Fast Build with Maven
         run: |
-          ./mvnw --show-version --errors --batch-mode \
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
             -Dmaven.repo.local=.m2/repository \
             verify -PfastSkip -DskipTests -Dcyclonedx.skip=false \
             deploy:deploy -DaltDeploymentRepository="dogfood::file://$(pwd)/target/staging"
@@ -97,7 +97,7 @@ jobs:
           name: compile-artifact
       - name: Full Build with Maven
         run: |
-          ./mvnw --show-version --errors --batch-mode \
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
               -Dmaven.repo.local=.m2/repository \
               verify -DskipTests
       - uses: actions/upload-artifact@v4
@@ -154,14 +154,42 @@ jobs:
           name: compile-artifact
       - name: Build with Maven and run unit tests
         run: |
-          ./mvnw --show-version --errors --batch-mode \
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
               -Dmaven.repo.local=.m2/repository \
               verify \
               -PfastSkip -Dcyclonedx.skip=false \
               -Djava8.home="${JAVA_HOME_8_X64}" \
               -Djava17.home="${JAVA_HOME_17_X64}" \
               -Djava21.home="${JAVA_HOME_21_X64}"
 
+  rewrite:
+    needs: compile
+    timeout-minutes: 90
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '11'
+      - uses: actions/cache@v4
+        with:
+          key: maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: maven-
+          path: .m2/repository
+          enableCrossOsArchive: true
+      - uses: actions/download-artifact@v4
+        with:
+          name: compile-artifact
+      - name: Rewrite
+        run: |
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
+              -Dmaven.repo.local=.m2/repository \
+              clean rewrite:dryRun
+
   dogfood:
     needs: compile
     timeout-minutes: 30
@@ -232,7 +260,7 @@ jobs:
           echo "::endgroup::"
 
           echo "::group::Run ./mvnw verify"
-          ./mvnw --show-version --errors --batch-mode \
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
             --settings "${maven_settings_file}" \
             -Dmaven.repo.local=.m2/repository \
             verify \
@@ -272,7 +300,7 @@ jobs:
           name: compile-artifact
       - name: Generate rule docs
         run: |
-          ./mvnw --show-version --errors --batch-mode \
+          ./mvnw --show-version --errors --batch-mode --no-transfer-progress \
             -Dmaven.repo.local=.m2/repository \
             verify \
             -Pgenerate-rule-docs,fastSkip \

docs/pages/pmd/devdocs/contributing/contributing.md

@@ -81,6 +81,20 @@ There are various channels, on which you can ask questions:
 
 *   Ask your question our [PMD Guru at Gurubase](https://gurubase.io/g/pmd).
 
+## 🚀 Code Transformation & Automated Rewriting
+*(Advanced Refactoring, Modernization, and Bulk Code Changes)*
+
+#### 🔧 Automated rewriting of source code to
+- **Refactor** safely (e.g., rename methods, migrate APIs)
+- **Modernize** (e.g., Java 8 → Java 17 features)
+- **Patterns** (e.g., replace `Vector` with `ArrayList`)
+- **Enforce conventions** (e.g., JUnit's naming rules)
+
+The build system incorporates [OpenRewrite](https://docs.openrewrite.org/) capabilities for automated code transformations.
+
+- Check for compliance with `mvn rewrite:dryRun`.
+- Apply suggestions with `mvn rewrite:run`.
+
 ## Code Style
 
 PMD uses [Checkstyle](https://checkstyle.org/) to enforce a common code style.
@@ -89,6 +103,8 @@ See [pmd-checkstyle-config.xml](https://github.com/pmd/build-tools/blob/main/src
 [the eclipse configuration files](https://github.com/pmd/build-tools/tree/main/eclipse) that can
 be imported into a fresh workspace.
 
+Rewrite will automatically apply all rules, by using the CodeCleanup recipe like in this [showcase](https://docs.openrewrite.org/running-recipes/popular-recipe-guides/automatically-fix-checkstyle-violations). 
+
 ## Add yourself as contributor
 
 We use [All Contributors](https://allcontributors.org/en) - all our contributors are listed on the page [Credits](pmd_projectdocs_credits.html).

pmd-ant/src/main/java/net/sourceforge/pmd/ant/Formatter.java

@@ -87,16 +87,16 @@ private void start(String baseDir) {
         Charset charset;
         {
             String s = (String) properties.get("encoding");
-            if (null == s) {
+            if (s == null) {
 
                 if (toConsole) {
                     s = getConsoleEncoding();
-                    if (null == s) {
+                    if (s == null) {
                         s = System.getProperty("file.encoding");
                     }
                 }
 
-                if (null == s) {
+                if (s == null) {
                     charset = StandardCharsets.UTF_8;
                 } else {
                     charset = Charset.forName(s);

pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/ast/ASTUserInterface.java

@@ -25,6 +25,6 @@ protected <P, R> R acceptApexVisitor(ApexVisitor<? super P, ? extends R> visitor
      * The type name does NOT include type arguments.
      */
     public String getSuperInterfaceName() {
-        return node.getExtendsTypes().stream().map(TypeRef::asTypeErasedString).findFirst().orElse("");
+        return node.getExtendsTypes().stream().findFirst().map(TypeRef::asTypeErasedString).orElse("");
     }
 }

pmd-core/src/main/java/net/sourceforge/pmd/internal/Slf4jSimpleConfiguration.java

@@ -73,7 +73,7 @@ public static void reconfigureDefaultLogLevel(Level level) {
             Map<String, Logger> loggerMap = (Map<String, Logger>) loggerMapField.get(loggerFactory);
             for (Logger logger : loggerMap.values()) {
                 if (logger.getName().startsWith(PMD_ROOT_LOGGER)
-                    && simpleLoggerClass.isAssignableFrom(logger.getClass())) {
+                    && simpleLoggerClass.isInstance(logger)) {
                     String newConfiguredLevel = (String) levelStringMethod.invoke(logger);
                     int newLogLevel = newDefaultLogLevel;
                     if (newConfiguredLevel != null) {
@@ -132,7 +132,7 @@ public static boolean isSimpleLogger() {
         try {
             ILoggerFactory loggerFactory = LoggerFactory.getILoggerFactory();
             Class<?> loggerFactoryClass = loggerFactory.getClass().getClassLoader().loadClass(SIMPLE_LOGGER_FACTORY_CLASS);
-            return loggerFactoryClass.isAssignableFrom(loggerFactory.getClass());
+            return loggerFactoryClass.isInstance(loggerFactory);
         } catch (ClassNotFoundException e) {
             // not slf4j simple logger
             return false;

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/ParseException.java

@@ -6,7 +6,6 @@
 
 import java.util.LinkedHashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -94,7 +93,7 @@ private static String makeMessage(@NonNull JavaccToken currentToken,
             expectedBranches.add(expected.toString());
         }
 
-        String expected = expectedBranches.stream().collect(Collectors.joining(System.lineSeparator() + "    "));
+        String expected = String.join(System.lineSeparator() + "    ", expectedBranches);
 
         StringBuilder retval = new StringBuilder("Encountered ");
         if (maxSize > 1) {

pmd-core/src/main/java/net/sourceforge/pmd/lang/metrics/MetricsUtil.java

@@ -6,7 +6,6 @@
 
 import java.util.DoubleSummaryStatistics;
 import java.util.Objects;
-import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 import net.sourceforge.pmd.lang.ast.Node;
@@ -65,8 +64,7 @@ public static <O extends Node> DoubleSummaryStatistics computeStatistics(Metric<
         Objects.requireNonNull(ops, NULL_NODE_MESSAGE);
 
         return StreamSupport.stream(ops.spliterator(), false)
-                            .filter(key::supports)
-                            .collect(Collectors.summarizingDouble(op -> computeMetric(key, op, options).doubleValue()));
+                .filter(key::supports).mapToDouble(op -> computeMetric(key, op, options).doubleValue()).summaryStatistics();
     }
 
     /**

pmd-core/src/main/java/net/sourceforge/pmd/lang/rule/AbstractRule.java

@@ -286,7 +286,7 @@ public boolean equals(Object o) {
 
         AbstractRule that = (AbstractRule) o;
         return Objects.equals(getName(), that.getName())
-                && Objects.equals(getPriority(), that.getPriority())
+                && getPriority() == that.getPriority()
                 && super.equals(o);
     }
 

pmd-core/src/main/java/net/sourceforge/pmd/lang/rule/xpath/impl/AttributeAxisIterator.java

@@ -132,7 +132,7 @@ private boolean isConsideredReturnType(Method method) {
                 try {
                     // ignore type variables, such as List<N>… we could check all bounds, but probably it's overkill
                     Type actualTypeArgument = ((ParameterizedType) t).getActualTypeArguments()[0];
-                    if (!TypeVariable.class.isAssignableFrom(actualTypeArgument.getClass())) {
+                    if (!TypeVariable.class.isInstance(actualTypeArgument)) {
                         Class<?> elementKlass = Class.forName(actualTypeArgument.getTypeName());
                         return CONSIDERED_RETURN_TYPES.contains(elementKlass) || elementKlass.isEnum();
                     }

pmd-core/src/main/java/net/sourceforge/pmd/lang/rule/xpath/internal/AstElementNode.java

@@ -226,7 +226,7 @@ public String getStringValue() {
         // potentially text nodes
         return node.descendants(TextNode.class).toStream()
                 .map(TextNode::getText)
-                .collect(Collectors.joining(""));
+                .collect(Collectors.joining());
     }
 
     @Override