Add maven-enforcer-plugin to ensure that a valid JVM version is used (#…

…683)

Signed-off-by: Ryan Emerson <[email protected]>

pom.xml

@@ -13,10 +13,11 @@
     <keycloak.version>999.0.0-SNAPSHOT</keycloak.version>
     <junit5.version>5.9.3</junit5.version>
     <httpclient.version>4.5.14</httpclient.version>
+    <maven.enforcer.plugin.version>3.4.1</maven.enforcer.plugin.version>
     <maven.surefire.plugin.version>3.1.2</maven.surefire.plugin.version>
-    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.source>17</maven.compiler.source>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.target>17</maven.compiler.target>
     <encoding>UTF-8</encoding>
   </properties>
 
@@ -123,6 +124,27 @@
         <artifactId>maven-surefire-plugin</artifactId>
         <version>${maven.surefire.plugin.version}</version>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>${maven.enforcer.plugin.version}</version>
+        <executions>
+          <execution>
+            <id>enforce-java</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <requireJavaVersion>
+                  <!-- Java 21 is not currently supported by Scala 2.12.x, so we enforce the previous LTS release Java 17 -->
+                  <version>[${maven.compiler.source},18)</version>
+                </requireJavaVersion>
+              </rules>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>