Fix Tests on JDK 21

Issue gh-13811

build.gradle

@@ -144,6 +144,7 @@ subprojects {
 	tasks.withType(JavaCompile).configureEach {
 		options.encoding = "UTF-8"
 		options.compilerArgs.add("-parameters")
+		options.release.set(17)
 	}
 }
 

core/src/test/java/org/springframework/security/core/JavaVersionTests.java

@@ -33,20 +33,11 @@ public class JavaVersionTests {
 
 	private static final int JDK17_CLASS_VERSION = 61;
 
-	private static final int JDK21_CLASS_VERSION = 65;
-
 	@Test
-	@EnabledOnJre(JRE.JAVA_17)
 	public void authenticationWhenJdk17ThenCorrectJdkCompatibility() throws Exception {
 		assertClassVersion(Authentication.class, JDK17_CLASS_VERSION);
 	}
 
-	@Test
-	@EnabledOnJre(JRE.JAVA_21)
-	public void authenticationWhenJdk21ThenCorrectJdkCompatibility() throws Exception {
-		assertClassVersion(Authentication.class, JDK21_CLASS_VERSION);
-	}
-
 	private void assertClassVersion(Class<?> clazz, int classVersion) throws Exception {
 		String classResourceName = clazz.getName().replaceAll("\\.", "/") + ".class";
 		try (InputStream input = Thread.currentThread().getContextClassLoader()