fix: rename custom Maven java.* properties to jdk.*

sebthom · sebthom · commit 030b800ca355 · 2026-01-27T22:55:46.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,32 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+- **BREAKING** renamed `java.*` Maven properties to `jdk.*` to prevent clashing with the JVM’s standard system properties
+  `java.version`/`java.vendor` (e.g. via `-Djava.*`) and misleading Maven/plugin prerequisite checks when Maven runs on a newer JDK while toolchains target an older JDK.
+
+  | Old property                     | New property
+  | -------------------------------- | -------------
+  | `java.version`                   | `jdk.version`
+  | `java.vendor`                    | `jdk.vendor`
+  | `java.version.unit-tests`        | `jdk.version.unit-tests`
+  | `java.vendor.unit-tests`         | `jdk.vendor.unit-tests`
+  | `java.version.integration-tests` | `jdk.version.integration-tests`
+  | `java.vendor.integration-tests`  | `jdk.vendor.integration-tests`
+  | `java.version.verify`            | `jdk.version.verify`
+  | `java.vendor.verify`             | `jdk.vendor.verify`
+- upgrade Eclipse Java Compiler 3.43.0 -> 3.44.0
+- Maven plugin upgrades:
+  - central-publishing-maven-plugin 0.9.0 -> 0.10.0
+  - checkstyle 12.2.0 -> 13.0.0
+  - exec-maven-plugin 3.6.2 -> 3.6.3
+  - groovy.version 5.0.3 -> 5.0.4
+  - gmavenplus-plugin 4.2.1 -> 4.3.0
+  - japicmp-maven-plugin 0.25.0 -> 0.25.4
+  - license-maven-plugin) from 2.7.0 to 2.7.1
+  - maven-release-plugin 3.3.0 -> 3.3.1
+  - versions-maven-plugin 2.20.1 -> 2.21.0
+
 
 ## [7.0.0] - 2025-12-10
 
diff --git a/README.md b/README.md
@@ -21,16 +21,16 @@ Opinionated best practices [Maven](https://maven.apache.org) parent project with
     ```xml
     <properties>
        <!-- use Oracle JDK 11 for compilation -->
-       <java.version>11</java.version>
-       <java.vendor>oracle</java.vendor>
+       <jdk.version>11</jdk.version>
+       <jdk.vendor>oracle</jdk.vendor>
 
        <!-- use Open JDK 17 for running unit tests -->
-       <java.version.unit-tests>17</java.version.unit-tests>
-       <java.vendor.unit-tests>openjdk</java.vendor.unit-tests>
+       <jdk.version.unit-tests>17</jdk.version.unit-tests>
+       <jdk.vendor.unit-tests>openjdk</jdk.vendor.unit-tests>
 
        <!-- use Open JDK 21 for running integration tests -->
-       <java.version.integration-tests>21</java.version.integration-tests>
-       <java.vendor.integration-tests>openjdk</java.vendor.integration-tests>
+       <jdk.version.integration-tests>21</jdk.version.integration-tests>
+       <jdk.vendor.integration-tests>openjdk</jdk.vendor.integration-tests>
     </properties>
     ```
 - Configures the [Eclipse Java Compiler](https://mvnrepository.com/artifact/org.eclipse.jdt.core.compiler/ecj) instead of javac:
diff --git a/pom.xml b/pom.xml
@@ -85,21 +85,21 @@ check for new dependency/plugin updates using:
       <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
       <maven-resources-plugin.propertiesEncoding>ISO-8859-1</maven-resources-plugin.propertiesEncoding>
 
-      <java.version>17</java.version>
-      <java.vendor>default</java.vendor>
+      <jdk.version>17</jdk.version>
+      <jdk.vendor>default</jdk.vendor>
 
-      <java.version.unit-tests>${java.version}</java.version.unit-tests>
-      <java.vendor.unit-tests>${java.vendor}</java.vendor.unit-tests>
+      <jdk.version.unit-tests>${jdk.version}</jdk.version.unit-tests>
+      <jdk.vendor.unit-tests>${jdk.vendor}</jdk.vendor.unit-tests>
 
-      <java.version.integration-tests>${java.version.unit-tests}</java.version.integration-tests>
-      <java.vendor.integration-tests>${java.vendor.unit-tests}</java.vendor.integration-tests>
+      <jdk.version.integration-tests>${jdk.version.unit-tests}</jdk.version.integration-tests>
+      <jdk.vendor.integration-tests>${jdk.vendor.unit-tests}</jdk.vendor.integration-tests>
 
-      <java.version.verify>${java.version}</java.version.verify>
-      <java.vendor.verify>${java.vendor}</java.vendor.verify>
+      <jdk.version.verify>${jdk.version}</jdk.version.verify>
+      <jdk.vendor.verify>${jdk.vendor}</jdk.vendor.verify>
 
       <!-- https://central.sonatype.com/artifact/org.eclipse.jdt/ecj/ -->
       <!-- https://github.com/eclipse-jdt/eclipse.jdt.core.git -->
-      <eclipse-java-compiler.version>3.43.0</eclipse-java-compiler.version>
+      <eclipse-java-compiler.version>3.44.0</eclipse-java-compiler.version>
 
       <groovy.groupId>org.apache.groovy</groovy.groupId> <!-- old: org.codehaus.groovy -->
       <groovy.version>5.0.4</groovy.version>
@@ -329,7 +329,7 @@ check for new dependency/plugin updates using:
             /*
              * loading/locating eclipse Java compiler artifact
              */
-            def javaVersion = getProjectProp("java.version");
+            def javaVersion = getProjectProp("jdk.version");
             def javaMajorVersion = Integer.parseInt(javaVersion.indexOf(".") > -1 ? javaVersion.substring(0, javaVersion.indexOf(".")) : javaVersion);
             def ecjVersion = javaMajorVersion < 17 ? "3.33.0" : project.properties["eclipse-java-compiler.version"]; def ecjArtifactMeta = artifactFactory.createArtifactWithClassifier("org.eclipse.jdt", "ecj", ecjVersion, "jar", null); def ecjArtifact = artifactResolver.resolve(new org.apache.maven.artifact.resolver.ArtifactResolutionRequest() .setArtifact(ecjArtifactMeta) .setLocalRepository(session.localRepository)
                   .setRemoteRepositories(project.remoteArtifactRepositories)
@@ -351,7 +351,7 @@ check for new dependency/plugin updates using:
              */
             def compileJDKSpec = [
                "version": javaVersion,
-               "vendor": getProjectProp("java.vendor")
+               "vendor": getProjectProp("jdk.vendor")
             ]
             /* https://github.com/apache/maven/tree/master/maven-core/src/main/java/org/apache/maven/toolchain */
             def compileJDKs = session.lookup("org.apache.maven.toolchain.ToolchainManager")?.getToolchains(session, "jdk", compileJDKSpec);
@@ -808,7 +808,7 @@ check for new dependency/plugin updates using:
                      <skip>${skip.enforcer.enforce-bytecode-version}</skip>
                      <rules>
                         <enforceBytecodeVersion>
-                           <maxJdkVersion>${java.version}</maxJdkVersion>
+                           <maxJdkVersion>${jdk.version}</maxJdkVersion>
                            <ignoreOptionals>true</ignoreOptionals>
                            <ignoredScopes>
                               <ignoredScope>provided</ignoredScope>
@@ -958,7 +958,7 @@ check for new dependency/plugin updates using:
             </executions>
             <!-- the source and target configuration is added here for the maven-javadoc-plugin and the m2eclipse project configuration which rely on these values-->
             <configuration>
-               <release>${java.version}</release>
+               <release>${jdk.version}</release>
             </configuration>
          </plugin>
          <plugin>
@@ -994,7 +994,7 @@ check for new dependency/plugin updates using:
                         -time<!-- display speed information. -->
                         -showversion<!-- display the build number of the compiler -->
                         -d "${project.build.outputDirectory}"
-                        --release ${java.version}
+                        --release ${jdk.version}
                         -cp "${custom.compileClasspathElements}"<!-- <classpath /> doesn't work here as it misses runtime dependencies -->
                         ${custom.ecjSourcePaths}
                      </commandlineArgs>
@@ -1024,7 +1024,7 @@ check for new dependency/plugin updates using:
                         -time<!-- display speed information. -->
                         -showversion<!-- display the build number of the compiler -->
                         -d "${project.build.testOutputDirectory}"
-                        --release ${java.version}
+                        --release ${jdk.version}
                         -cp "${custom.test.classpathElements}"<!-- <classpath /> doesn't work here as it misses runtime dependencies -->
                         ${custom.test.ecjSourcePaths}
                      </commandlineArgs>
@@ -1276,8 +1276,8 @@ check for new dependency/plugin updates using:
                      <configuration>
                         <toolchains>
                            <jdk>
-                              <version>${java.version}</version>
-                              <vendor>${java.vendor}</vendor>
+                              <version>${jdk.version}</version>
+                              <vendor>${jdk.vendor}</vendor>
                            </jdk>
                         </toolchains>
                      </configuration>
@@ -1291,8 +1291,8 @@ check for new dependency/plugin updates using:
                      <configuration>
                         <toolchains>
                            <jdk>
-                              <version>${java.version.unit-tests}</version>
-                              <vendor>${java.vendor.unit-tests}</vendor>
+                              <version>${jdk.version.unit-tests}</version>
+                              <vendor>${jdk.vendor.unit-tests}</vendor>
                            </jdk>
                         </toolchains>
                      </configuration>
@@ -1306,8 +1306,8 @@ check for new dependency/plugin updates using:
                      <configuration>
                         <toolchains>
                            <jdk>
-                              <version>${java.version.integration-tests}</version>
-                              <vendor>${java.vendor.integration-tests}</vendor>
+                              <version>${jdk.version.integration-tests}</version>
+                              <vendor>${jdk.vendor.integration-tests}</vendor>
                            </jdk>
                         </toolchains>
                      </configuration>
@@ -1321,8 +1321,8 @@ check for new dependency/plugin updates using:
                      <configuration>
                         <toolchains>
                            <jdk>
-                              <version>${java.version.verify}</version>
-                              <vendor>${java.vendor.verify}</vendor>
+                              <version>${jdk.version.verify}</version>
+                              <vendor>${jdk.vendor.verify}</vendor>
                            </jdk>
                         </toolchains>
                      </configuration>
@@ -1660,7 +1660,7 @@ check for new dependency/plugin updates using:
                <configuration>
                   <skip>${skip.maven.javadoc}</skip>
 
-                  <source>${java.version}</source>
+                  <source>${jdk.version}</source>
 
                   <charset>${project.build.sourceEncoding}</charset>
                   <encoding>${project.build.sourceEncoding}</encoding>
diff --git a/src/test/project/pom.xml b/src/test/project/pom.xml
@@ -18,8 +18,8 @@
   <artifactId>vegardit-maven-parent.test</artifactId>
 
   <properties>
-    <java.version.unit-tests>21</java.version.unit-tests>
-    <maven.surefire.args>-Djava.version.unit-tests=${java.version.unit-tests}</maven.surefire.args>
+    <jdk.version.unit-tests>21</jdk.version.unit-tests>
+    <maven.surefire.args>-Djdk.version.unit-tests=${jdk.version.unit-tests}</maven.surefire.args>
     <maven.deploy.skip>true</maven.deploy.skip>
     <central-publishing-maven-plugin.excludedArtifacts>${project.artifactId}</central-publishing-maven-plugin.excludedArtifacts>
   </properties>
diff --git a/src/test/project/src/test/java/com/vegardit/maven/parent/test/RuntimeJavaVersionTest.java b/src/test/project/src/test/java/com/vegardit/maven/parent/test/RuntimeJavaVersionTest.java
@@ -26,7 +26,7 @@ public static int getJavaCompilerVersion(final Class<?> clazz) throws IOExceptio
     * This tests if the following config in the pom.xml is effective
     * <pre>{@code
     *   <properties>
-    *     <java.version.unit-tests>21</java.version.unit-tests>
+    *     <jdk.version.unit-tests>21</jdk.version.unit-tests>
     *   </properties>
     * }</pre>
     */
@@ -35,8 +35,9 @@ void ensureRightJDKsAreUsed() throws Exception {
       System.out.println("Compile Java Version: " + getJavaCompilerVersion(Shape.class));
       System.out.println("Runtime Java Version: " + Runtime.version().feature());
       System.out.println("java.version: " + System.getProperty("java.version"));
-      System.out.println("java.version.unit-tests: " + System.getProperty("java.version.unit-tests"));
+      System.out.println("jdk.version: " + System.getProperty("jdk.version"));
+      System.out.println("jdk.version.unit-tests: " + System.getProperty("jdk.version.unit-tests"));
       assertEquals(17, getJavaCompilerVersion(Shape.class));
-      assertEquals(Runtime.version().feature(), Integer.getInteger("java.version.unit-tests"));
+      assertEquals(Runtime.version().feature(), Integer.getInteger("jdk.version.unit-tests"));
    }
 }
