Update to Java 21

Change-Id: I68d241c6a1d8da97f212647a3da2ac3793fe4f72
diff --git a/pom.xml b/pom.xml
index 5cc8cba..78392f6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -59,7 +59,7 @@
   </developers>
 
   <properties>
-    <java.version>17</java.version>
+    <java.version>21</java.version>
     <jersey.version>3.1.11</jersey.version>
     <log4j.version>2.25.2</log4j.version>
     <jackson.version>2.18.1</jackson.version>