Polish contribution

See gh-36948

spring-core/src/test/java/org/springframework/util/xml/XmlValidationModeDetectorTests.java

@@ -44,7 +44,8 @@ class XmlValidationModeDetectorTests {
 		"dtdWithTrailingComment.xml",
 		"dtdWithTrailingCommentAcrossMultipleLines.xml",
 		"dtdWithCommentOnNextLine.xml",
-		"dtdWithMultipleComments.xml"
+		"dtdWithMultipleComments.xml",
+		"dtdWithDoctypeInMultiLineCommentBody.xml"
 	})
 	void dtdDetection(String fileName) throws Exception {
 		assertValidationMode(fileName, VALIDATION_DTD);
@@ -56,7 +57,8 @@ class XmlValidationModeDetectorTests {
 		"xsdWithMultipleComments.xml",
 		"xsdWithDoctypeInComment.xml",
 		"xsdWithDoctypeInOpenCommentWithAdditionalCommentOnSameLine.xml",
-		"xsdWithDoctypeInMultiLineCommentBody.xml"
+		"xsdWithDoctypeInMultiLineCommentBody.xml",
+		"xsdWithMultipleDoctypesInMultiLineCommentBody.xml"
 	})
 	void xsdDetection(String fileName) throws Exception {
 		assertValidationMode(fileName, VALIDATION_XSD);

spring-core/src/test/resources/org/springframework/util/xml/dtdWithDoctypeInMultiLineCommentBody.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+	DOCTYPE
+-->
+<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "https://www.springframework.org/dtd/spring-beans-2.0.dtd">
+<beans>
+
+</beans>

spring-core/src/test/resources/org/springframework/util/xml/xsdWithMultipleDoctypesInMultiLineCommentBody.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+	xxx DOCTYPE xxx
+	yyy
+	zzz DOCTYPE zzz
+-->
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="https://www.springframework.org/schema/beans
+		https://www.springframework.org/schema/beans/spring-beans.xsd">
+
+</beans>