Polish "Fix Jetty ConnectionLimit configuration"

See gh-39052

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactoryTests.java

@@ -39,6 +39,7 @@ import org.apache.hc.client5.http.impl.classic.HttpClients;
 import org.apache.hc.core5.http.Header;
 import org.apache.hc.core5.http.HttpResponse;
 import org.apache.jasper.servlet.JspServlet;
+import org.assertj.core.api.InstanceOfAssertFactories;
 import org.awaitility.Awaitility;
 import org.eclipse.jetty.ee10.servlet.ErrorPageErrorHandler;
 import org.eclipse.jetty.ee10.servlet.ServletHolder;
@@ -46,6 +47,7 @@ import org.eclipse.jetty.ee10.webapp.AbstractConfiguration;
 import org.eclipse.jetty.ee10.webapp.ClassMatcher;
 import org.eclipse.jetty.ee10.webapp.Configuration;
 import org.eclipse.jetty.ee10.webapp.WebAppContext;
+import org.eclipse.jetty.server.AbstractConnector;
 import org.eclipse.jetty.server.ConnectionLimit;
 import org.eclipse.jetty.server.Connector;
 import org.eclipse.jetty.server.Handler;
@@ -72,7 +74,6 @@ import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.assertj.core.api.InstanceOfAssertFactories.LIST;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.inOrder;
@@ -551,7 +552,9 @@ class JettyServletWebServerFactoryTests extends AbstractServletWebServerFactoryT
 		Server server = ((JettyWebServer) this.webServer).getServer();
 		assertThat(server.getConnectors()).isEmpty();
 		ConnectionLimit connectionLimit = server.getBean(ConnectionLimit.class);
-		assertThat(connectionLimit).extracting("_connectors", LIST).hasSize(1);
+		assertThat(connectionLimit).extracting("_connectors")
+			.asInstanceOf(InstanceOfAssertFactories.list(AbstractConnector.class))
+			.hasSize(1);
 	}
 
 	@Override