fix: update jdk

Author: Angular2Guy

source-sink/pom.xml

@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.5.0</version>
+		<version>3.5.6</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>de.xxx</groupId>
@@ -38,7 +38,7 @@
 	</scm>
 	<properties>
 		<jaxb-maven-plugin.version>4.0.8</jaxb-maven-plugin.version>
-		<java.version>25</java.version>
+        <java.version>21</java.version>
 		<kotlin.version>1.9.25</kotlin.version>
 	</properties>
 	<dependencies>
@@ -112,7 +112,6 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<configuration>
-                    <jvmTarget>21</jvmTarget>
 					<args>
 						<arg>-Xjsr305=strict</arg>
 					</args>