Merge branch '2.6.x' into 2.7.x

Closes gh-29557

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactory.java

@@ -232,7 +232,7 @@ public class JettyServletWebServerFactory extends AbstractServletWebServerFactor
 	 */
 	protected final void configureWebAppContext(WebAppContext context, ServletContextInitializer... initializers) {
 		Assert.notNull(context, "Context must not be null");
-		context.getAliasChecks().clear();
+		context.clearAliasChecks();
 		context.setTempDirectory(getTempDirectory());
 		if (this.resourceLoader != null) {
 			context.setClassLoader(this.resourceLoader.getClassLoader());