From 3d0120b4a91877d803f1f22bb3aea861f36377f4 Mon Sep 17 00:00:00 2001
From: "David M. Lloyd" <david.lloyd@redhat.com>
Date: Wed, 20 Sep 2023 07:45:40 -0500
Subject: [PATCH] Support up to Java 21

---
 README.adoc |   4 +
 pom.xml     | 242 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 245 insertions(+), 1 deletion(-)

diff --git a/README.adoc b/README.adoc
index cfa7547..7ac50e5 100644
--- a/README.adoc
+++ b/README.adoc
@@ -44,6 +44,8 @@ In order to do so, it is expected that the following system property or properti
 * `java17.home`: this property must be set to the location of a Java 17 JDK installation
 * `java18.home`: this property must be set to the location of a Java 18 JDK installation
 * `java19.home`: this property must be set to the location of a Java 19 JDK installation
+* `java20.home`: this property must be set to the location of a Java 20 JDK installation
+* `java21.home`: this property must be set to the location of a Java 21 JDK installation
 
 In order to simplify development, it is recommended to project maintainers to set these
 properties in your personal Maven `settings.xml` file.
@@ -163,5 +165,7 @@ Note that this configuration causes the default `JAVA_HOME` environment to be se
 |build-test-java17|Run tests for Java 17 when `java17.home` is set and JDK 18 or later is used.|<<mr-jar-testing>>
 |build-test-java18|Run tests for Java 18 when `java18.home` is set and JDK 19 or later is used.|<<mr-jar-testing>>
 |build-test-java19|Run tests for Java 19 when `java19.home` is set and JDK 20 or later is used.|<<mr-jar-testing>>
+|build-test-java20|Run tests for Java 20 when `java20.home` is set and JDK 21 or later is used.|<<mr-jar-testing>>
+|build-test-java21|Run tests for Java 21 when `java21.home` is set and JDK 22 or later is used.|<<mr-jar-testing>>
 |===
 
diff --git a/pom.xml b/pom.xml
index eea287b..c6c7974 100644
--- a/pom.xml
+++ b/pom.xml
@@ -772,7 +772,7 @@
       </build>
     </profile>
 
-    <!-- This profile is activated when Java 18 or later is used to build -->
+    <!-- This profile is activated when Java 19 or later is used to build -->
     <profile>
       <id>java19-mr-build</id>
       <activation>
@@ -816,6 +816,246 @@
         </plugins>
       </build>
     </profile>
+
+    <!--                 -->
+    <!-- Java 20 support -->
+    <!--                 -->
+
+    <!-- This profile is activated when the baseline JDK version running tests is Java 20 -->
+    <profile>
+      <id>java20-test-classpath</id>
+      <activation>
+        <jdk>[20,20)</jdk>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-surefire-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>default-test</id>
+                <configuration>
+                  <classesDirectory>${project.build.outputDirectory}/META-INF/versions/20</classesDirectory>
+                  <additionalClasspathElements>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/19</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/18</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/17</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}</additionalClasspathElement>
+                  </additionalClasspathElements>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+
+    <!-- This profile is activated when Java 20 or later is used to test a project that supports Java 19-->
+    <profile>
+      <id>java19-test</id>
+      <activation>
+        <jdk>[20,)</jdk>
+        <property>
+          <name>java19.home</name>
+        </property>
+        <file>
+          <exists>${basedir}/build-test-java19</exists>
+        </file>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-surefire-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>java19-test</id>
+                <phase>test</phase>
+                <goals>
+                  <goal>test</goal>
+                </goals>
+                <configuration>
+                  <jvm>${java19.home}/bin/java</jvm>
+                  <classesDirectory>${project.build.outputDirectory}/META-INF/versions/19</classesDirectory>
+                  <additionalClasspathElements>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/18</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/17</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}</additionalClasspathElement>
+                  </additionalClasspathElements>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+
+    <!-- This profile is activated when Java 20 or later is used to build -->
+    <profile>
+      <id>java20-mr-build</id>
+      <activation>
+        <jdk>[20,)</jdk>
+        <file>
+          <exists>${basedir}/src/main/java20</exists>
+        </file>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>compile-java20</id>
+                <phase>compile</phase>
+                <goals>
+                  <goal>compile</goal>
+                </goals>
+                <configuration>
+                  <release>20</release>
+                  <compileSourceRoots>
+                    <compileSourceRoot>${project.basedir}/src/main/java20</compileSourceRoot>
+                  </compileSourceRoots>
+                  <multiReleaseOutput>true</multiReleaseOutput>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+          <plugin>
+            <artifactId>maven-jar-plugin</artifactId>
+            <configuration>
+              <archive>
+                <manifestEntries>
+                  <Multi-Release>true</Multi-Release>
+                </manifestEntries>
+              </archive>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+
+    <!--                 -->
+    <!-- Java 21 support -->
+    <!--                 -->
+
+    <!-- This profile is activated when the baseline JDK version running tests is Java 21 -->
+    <profile>
+      <id>java21-test-classpath</id>
+      <activation>
+        <jdk>[21,21)</jdk>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-surefire-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>default-test</id>
+                <configuration>
+                  <classesDirectory>${project.build.outputDirectory}/META-INF/versions/21</classesDirectory>
+                  <additionalClasspathElements>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/20</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/19</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/18</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/17</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}</additionalClasspathElement>
+                  </additionalClasspathElements>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+
+    <!-- This profile is activated when Java 21 or later is used to test a project that supports Java 20-->
+    <profile>
+      <id>java20-test</id>
+      <activation>
+        <jdk>[21,)</jdk>
+        <property>
+          <name>java20.home</name>
+        </property>
+        <file>
+          <exists>${basedir}/build-test-java20</exists>
+        </file>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-surefire-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>java20-test</id>
+                <phase>test</phase>
+                <goals>
+                  <goal>test</goal>
+                </goals>
+                <configuration>
+                  <jvm>${java20.home}/bin/java</jvm>
+                  <classesDirectory>${project.build.outputDirectory}/META-INF/versions/20</classesDirectory>
+                  <additionalClasspathElements>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/19</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/18</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}/META-INF/versions/17</additionalClasspathElement>
+                    <additionalClasspathElement>${project.build.outputDirectory}</additionalClasspathElement>
+                  </additionalClasspathElements>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+
+    <!-- This profile is activated when Java 21 or later is used to build -->
+    <profile>
+      <id>java21-mr-build</id>
+      <activation>
+        <jdk>[21,)</jdk>
+        <file>
+          <exists>${basedir}/src/main/java21</exists>
+        </file>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>compile-java21</id>
+                <phase>compile</phase>
+                <goals>
+                  <goal>compile</goal>
+                </goals>
+                <configuration>
+                  <release>21</release>
+                  <compileSourceRoots>
+                    <compileSourceRoot>${project.basedir}/src/main/java21</compileSourceRoot>
+                  </compileSourceRoots>
+                  <multiReleaseOutput>true</multiReleaseOutput>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+          <plugin>
+            <artifactId>maven-jar-plugin</artifactId>
+            <configuration>
+              <archive>
+                <manifestEntries>
+                  <Multi-Release>true</Multi-Release>
+                </manifestEntries>
+              </archive>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
     <!-- MR JAR support ends here-->
   </profiles>
 </project>