Set release level to 21

Signed-off-by: Lukas Jungmann <lukas.jungmann@oracle.com>

Author: lukasj

api/pom.xml

@@ -97,6 +97,8 @@
         <extension.name>jakarta.annotation</extension.name>
         <vendor.name>Eclipse Foundation</vendor.name>
         <implementation.vendor.id>org.glassfish</implementation.vendor.id>
+
+        <maven.compiler.release>21</maven.compiler.release>
     </properties>
 
     <build>
@@ -195,14 +197,6 @@
                     <!-- check that year is correct -->
                     <ignoreYear>${copyright.ignoreyear}</ignoreYear>
                 </configuration>
-                <executions>
-                    <execution>
-                        <phase>validate</phase>
-                        <goals>
-                            <goal>check</goal>
-                        </goals>
-                    </execution>
-                </executions>
             </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
@@ -233,25 +227,10 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
-                    <release>9</release>
                     <compilerArgs>
                         <arg>-Xlint:all</arg>
                     </compilerArgs>
                 </configuration>
-                <executions>
-                    <execution>
-                        <id>base-compile</id>
-                        <goals>
-                            <goal>compile</goal>
-                        </goals>
-                        <configuration>
-                            <release>8</release>
-                            <excludes>
-                                <exclude>module-info.java</exclude>
-                            </excludes>
-                        </configuration>
-                    </execution>
-                </executions>
             </plugin>
             <plugin>
                 <groupId>org.glassfish.build</groupId>
@@ -340,7 +319,6 @@
                             <addDefaultEntries>false</addDefaultEntries>
                         </manifest>
                     </archive>
-                    <release>11</release>
                     <additionalOptions>--add-modules java.sql</additionalOptions>
                     <notimestamp>true</notimestamp>
                     <nosince>true</nosince>
@@ -359,7 +337,6 @@
                 <configuration>
                     <skip>${spotbugs.skip}</skip>
                     <threshold>${spotbugs.threshold}</threshold>
-                    <findbugsXmlWithMessages>true</findbugsXmlWithMessages>
                     <fork>true</fork>
                 </configuration>
             </plugin>