Switch the build to JDK 11

.github/workflows/build.yml

@@ -49,12 +49,15 @@ jobs:
         with:
           fetch-depth: 32
 
-      # JDK 8 and 11 is needed for the build.
+      # JDK 11 is used for the build.
+      # JDK 8 is used for the tests.
       # Search `maven-toolchains-plugin` usages for details.
       - name: Setup JDK
         uses: actions/setup-java@cd89f46ac9d01407894225f350157564c9c7cee2   # 3.12.0
         with:
           distribution: temurin
+          # The last provided Java version will be used and available globally.
+          # Other Java versions can be accessed through environment variables: `JAVA_HOME_<majorVersion>_<architecture>`
           java-version: |
             8
             11
@@ -68,9 +71,10 @@ jobs:
       - name: Build
         timeout-minutes: 60
         shell: bash
-        env:
-          JAVA_HOME: ${{ env.JAVA_HOME_8_X64 }}
-        run: ./mvnw clean install
+        run: |
+          ./mvnw \
+          -Pjava8-tests \
+          clean install
 
       - name: Upload Surefire Reports
         if: failure()
@@ -85,8 +89,6 @@ jobs:
         id: report-reproducible
         timeout-minutes: 10
         shell: bash
-        env:
-          JAVA_HOME: ${{ env.JAVA_HOME_8_X64 }}
         run: |
           ./mvnw \
           -DskipTests=true \
@@ -105,8 +107,6 @@ jobs:
       - name: Build site
         timeout-minutes: 10
         shell: bash
-        env:
-          JAVA_HOME: ${{ env.JAVA_HOME_8_X64 }}
         run: ./mvnw site
 
   merge:
@@ -138,12 +138,15 @@ jobs:
         with:
           fetch-depth: 32
 
-      # JDK 8 and 11 are needed for the build.
+      # JDK 11 is used for the build.
+      # JDK 8 is used for the tests.
       # Search `maven-toolchains-plugin` usages for details.
       - name: Setup JDK
         uses: actions/setup-java@cd89f46ac9d01407894225f350157564c9c7cee2   # 3.12.0
         with:
           distribution: temurin
+          # The last provided Java version will be used and available globally.
+          # Other Java versions can be accessed through environment variables: `JAVA_HOME_<majorVersion>_<architecture>`
           java-version: |
             8
             11
@@ -173,6 +176,5 @@ jobs:
             -DskipTests=true \
             package install:install deploy:deploy
         env:
-          JAVA_HOME: ${{ env.JAVA_HOME_8_X64 }}
           NEXUS_USER: ${{ secrets.NEXUS_USER }}
           NEXUS_PW: ${{ secrets.NEXUS_PW }}

.github/workflows/codeql-analysis.yml

@@ -62,22 +62,17 @@ jobs:
           # Prefix the list here with "+" to use these queries and those in the config file.
           # queries: ./path/to/local/query, your-org/your-repo/queries@main
 
-      # JDK 8 and 11 is needed for the build.
-      # Search `maven-toolchains-plugin` usages for details.
+      # JDK 11 is used for the build.
       - name: Setup JDK
         uses: actions/setup-java@cd89f46ac9d01407894225f350157564c9c7cee2   # 3.12.0
         with:
           distribution: temurin
-          java-version: |
-            8
-            11
+          java-version: 11
           cache: maven
 
       - name: Build with Maven
         timeout-minutes: 60
         shell: bash
-        env:
-          JAVA_HOME: ${{ env.JAVA_HOME_8_X64 }}
         run: |
           ./mvnw \
           --show-version --batch-mode --errors --no-transfer-progress \

.github/workflows/log4j-kafka-test.yml

@@ -41,7 +41,9 @@ jobs:
         uses: actions/setup-java@cd89f46ac9d01407894225f350157564c9c7cee2   # 3.12.0
         with:
           distribution: temurin
-          java-version: 8
+          java-version: |
+            8
+            11
           java-package: jdk
           architecture: x64
           cache: maven
@@ -58,4 +60,5 @@ jobs:
             --show-version --batch-mode --errors --no-transfer-progress --fail-at-end \
             -Dkafka.version=${{ matrix.version }} \
             -pl log4j-core-test -Dtest=Kafka*Test \
+            -P java8-tests \
             test

.mvn/jvm.config

@@ -0,0 +1,10 @@
+--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED

BUILDING.md

@@ -17,30 +17,23 @@
 
 # Requirements
 
-* JDK 8 and 9+
-* Apache Maven 3.x
+* JDK 11+
+* JDK 8 (optional)
+* Apache Maven 3.x (optional)
 * A modern Linux, OSX, or Windows host
 
-<a name="toolchains"></a>
-# Configuring Maven Toolchains
-
-Maven Toolchains is used to employ multiple JDKs required for compilation.
-You either need to have a user-level configuration in `~/.m2/toolchains.xml` or explicitly provide one to the Maven: `./mvnw --global-toolchains /path/to/toolchains.xml`.
-See [`.github/workflows/maven-toolchains.xml`](.github/workflows/maven-toolchains.xml) used by CI for a sample Maven Toolchains configuration.
-Note that this file requires `JAVA_HOME_8_X64` and `JAVA_HOME_11_X64` environment variables to be defined, though these can very well be hardcoded.
-
 <a name="building"></a>
 # Building the sources
 
 You can build and verify the sources as follows:
-
-    ./mvnw verify
-
+```sh
+./mvnw verify
+```
 `verify` goal runs validation and test steps next to building (i.e., compiling) the sources.
 To speed up the build, you can skip verification:
-
-    ./mvnw -DskipTests package
-
+```sh
+./mvnw -DskipTests package
+```
 If you want to install generated artifacts to your local Maven repository, replace above `verify` and/or `package` goals with `install`.
 
 <a name="dns"></a>
@@ -50,16 +43,46 @@ Note that if your `/etc/hosts` file does not include an entry for your computer'
 many unit tests may execute slow due to DNS lookups to translate your hostname to an IP address in
 [`InetAddress.getLocalHost()`](http://docs.oracle.com/javase/7/docs/api/java/net/InetAddress.html#getLocalHost()).
 To remedy this, you can execute the following:
+```sh
+printf '127.0.0.1 %s\n::1 %s\n' `hostname` `hostname` | sudo tee -a /etc/hosts
+```
 
-    printf '127.0.0.1 %s\n::1 %s\n' `hostname` `hostname` | sudo tee -a /etc/hosts
+<a name="java8-tests"></a>
+# Java 8 tests
+
+To test the library against the target JRE (JRE 8), you need to configure a JDK 8 toolchains as explained below and run Maven with the `java8-tests` profile:
+```sh
+./mvnw verify -Pjava8-tests
+```
+
+<a name="toolchains"></a>
+## Configuring Maven Toolchains
+
+Maven Toolchains is used to employ additional JDKs required for tests.
+You either need to have a user-level configuration in `~/.m2/toolchains.xml` or explicitly provide one to the Maven: `./mvnw --global-toolchains /path/to/toolchains.xml`.
+```xml
+<?xml version="1.0" encoding="UTF8"?>
+<toolchains>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.8.0_372</version>
+    </provides>
+    <configuration>
+      <jdkHome>/usr/lib/jvm/java-8-openjdk-amd64</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>
+```
 
 <a name="website"></a>
 # Building the website and manual
 
 You can build the website and manual as follows:
-
-    ./mvnw site
-
+```sh
+./mvnw site
+```
 And view it using a simple HTTP server, e.g., the one comes with the Python:
-
-    python3 -m http.server -d target/site
+```sh
+python3 -m http.server -d target/site
+```

log4j-api-java9/pom.xml

@@ -31,6 +31,7 @@
     <docLabel>API Documentation</docLabel>
     <projectDir>/api</projectDir>
     <maven.deploy.skip>true</maven.deploy.skip>
+    <maven.compiler.release>9</maven.compiler.release>
   </properties>
   <dependencies>
     <dependency>
@@ -65,6 +66,7 @@
           </execution>
         </executions>
       </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
@@ -77,62 +79,49 @@
             <goals>
               <goal>compile</goal>
             </goals>
-            <phase>compile</phase>
-            <configuration>
-              <jdkToolchain>
-                <version>[9, )</version>
-              </jdkToolchain>
-              <release>9</release>
-            </configuration>
           </execution>
-          <!-- We explicitly compile tests using Java 8 to work around SUREFIRE-2073 -->
           <execution>
             <id>default-test-compile</id>
             <goals>
               <goal>testCompile</goal>
             </goals>
             <phase>test-compile</phase>
           </execution>
-          <!-- Of course the 'module-info.java' needs Java 9 -->
-          <execution>
-            <id>test-compile-module</id>
-            <goals>
-              <goal>testCompile</goal>
-            </goals>
-            <phase>test-compile</phase>
-            <configuration>
-              <jdkToolchain>
-                <version>[9, )</version>
-              </jdkToolchain>
-              <release>9</release>
-              <compileSourceRoots>
-                <compileSourceRoot>${project.basedir}/src/test/java9</compileSourceRoot>
-              </compileSourceRoots>
-            </configuration>
-          </execution>
         </executions>
       </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
-        <configuration>
-          <systemPropertyVariables>
-            <java.awt.headless>true</java.awt.headless>
-          </systemPropertyVariables>
-          <jdkToolchain>
-            <version>[9, )</version>
-          </jdkToolchain>
-        </configuration>
         <executions>
           <execution>
             <id>test</id>
             <goals>
               <goal>test</goal>
             </goals>
-            <phase>test</phase>
           </execution>
         </executions>
       </plugin>
     </plugins>
   </build>
+
+  <profiles>
+    <profile>
+      <id>java8-tests</id>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-surefire-plugin</artifactId>
+            <configuration combine.self="override">
+              <reuseForks>false</reuseForks>
+              <systemPropertyVariables>
+                <java.awt.headless>true</java.awt.headless>
+              </systemPropertyVariables>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+  </profiles>
 </project>

log4j-api-java9/src/test/java9/org/apache/logging/log4j/util/java9/ModuleUtil.java → log4j-api-java9/src/test/java/org/apache/logging/log4j/util/java9/ModuleUtil.java

@@ -1,18 +1,18 @@
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
+ * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache license, Version 2.0
+ * The ASF licenses this file to you under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
+ * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the license for the specific language governing permissions and
- * limitations under the license.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 package org.apache.logging.log4j.util.java9;
 

log4j-api-test/pom.xml

@@ -106,6 +106,7 @@
   </dependencies>
   <build>
     <plugins>
+
       <plugin>
         <groupId>org.apache.felix</groupId>
         <artifactId>maven-bundle-plugin</artifactId>
@@ -117,24 +118,7 @@
           </instructions>
         </configuration>
       </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-compiler-plugin</artifactId>
-        <executions>
-          <execution>
-            <id>default-compile</id>
-            <!-- recompile everything for target VM except the module-info.java -->
-            <configuration>
-              <source>1.8</source>
-              <target>1.8</target>
-            </configuration>
-          </execution>
-        </executions>
-      </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-deploy-plugin</artifactId>
-      </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
@@ -164,6 +148,7 @@
           </execution>
         </executions>
       </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
@@ -172,6 +157,7 @@
           <excludedGroups>performance,smoke</excludedGroups>
         </configuration>
       </plugin>
+
     </plugins>
   </build>
 </project>