Fix Nullability

Signed-off-by: Josh Cummings <3627351+jzheaux@users.noreply.github.com>

core/src/main/java/org/springframework/security/task/DelegatingSecurityContextAsyncTaskExecutor.java

@@ -72,7 +72,7 @@ public class DelegatingSecurityContextAsyncTaskExecutor extends DelegatingSecuri
 	}
 
 	@Override
-	public final <T> Future<T> submit(Callable<T> task) {
+	public final <T extends @Nullable Object> Future<T> submit(Callable<T> task) {
 		return getDelegate().submit(wrap(task));
 	}
 

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/session/InMemoryOidcSessionRegistry.java

@@ -50,7 +50,7 @@ public final class InMemoryOidcSessionRegistry implements OidcSessionRegistry {
 	}
 
 	@Override
-	public OidcSessionInformation removeSessionInformation(String clientSessionId) {
+	public @Nullable OidcSessionInformation removeSessionInformation(String clientSessionId) {
 		OidcSessionInformation information = this.sessions.remove(clientSessionId);
 		if (information != null) {
 			this.logger.trace("Removed client session");

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/session/OidcSessionRegistry.java

@@ -16,6 +16,8 @@
 
 package org.springframework.security.oauth2.client.oidc.session;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.security.oauth2.client.oidc.authentication.logout.OidcLogoutToken;
 
 /**
@@ -44,7 +46,7 @@ public interface OidcSessionRegistry {
 	 * @param clientSessionId the client session
 	 * @return any found {@link OidcSessionInformation}, could be {@code null}
 	 */
-	OidcSessionInformation removeSessionInformation(String clientSessionId);
+	@Nullable OidcSessionInformation removeSessionInformation(String clientSessionId);
 
 	/**
 	 * Deregister the OIDC Provider sessions referenced by the provided OIDC Logout Token