Merge branch '2.2.x' into 2.3.x

Closes gh-23258

Author: philwebb

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/ErrorMvcAutoConfiguration.java

@@ -17,7 +17,6 @@
 package org.springframework.boot.autoconfigure.web.servlet.error;
 
 import java.nio.charset.StandardCharsets;
-import java.util.Date;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -207,7 +206,7 @@ public void render(Map<String, ?> model, HttpServletRequest request, HttpServlet
 			}
 			response.setContentType(TEXT_HTML_UTF8.toString());
 			StringBuilder builder = new StringBuilder();
-			Date timestamp = (Date) model.get("timestamp");
+			Object timestamp = model.get("timestamp");
 			Object message = model.get("message");
 			Object trace = model.get("trace");
 			if (response.getContentType() == null) {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/error/ErrorMvcAutoConfigurationTests.java

@@ -16,6 +16,9 @@
 
 package org.springframework.boot.autoconfigure.web.servlet.error;
 
+import java.time.Clock;
+import java.util.Map;
+
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
@@ -65,6 +68,22 @@ void renderContainsViewWithExceptionDetails() {
 		});
 	}
 
+	@Test
+	void renderCanUseJavaTimeTypeAsTimestamp() throws Exception { // gh-23256
+		this.contextRunner.run((context) -> {
+			View errorView = context.getBean("error", View.class);
+			ErrorAttributes errorAttributes = context.getBean(ErrorAttributes.class);
+			DispatcherServletWebRequest webRequest = createWebRequest(new IllegalStateException("Exception message"),
+					false);
+			Map<String, Object> attributes = errorAttributes.getErrorAttributes(webRequest, true);
+			attributes.put("timestamp", Clock.systemUTC().instant());
+			errorView.render(attributes, webRequest.getRequest(), webRequest.getResponse());
+			assertThat(webRequest.getResponse().getContentType()).isEqualTo("text/html;charset=UTF-8");
+			String responseString = ((MockHttpServletResponse) webRequest.getResponse()).getContentAsString();
+			assertThat(responseString).contains("This application has no explicit mapping for /error");
+		});
+	}
+
 	@Test
 	void renderWhenAlreadyCommittedLogsMessage(CapturedOutput output) {
 		this.contextRunner.run((context) -> {