Restore check for jar root existence (now via getEntryName/getJarEntry)

Closes gh-34607

Author: jhoeller

spring-core/src/main/java/org/springframework/core/io/AbstractFileResolvingResource.java

@@ -56,6 +56,7 @@ public boolean exists() {
 				// Try a URL connection content-length header
 				URLConnection con = url.openConnection();
 				customizeConnection(con);
+
 				HttpURLConnection httpCon = (con instanceof HttpURLConnection huc ? huc : null);
 				if (httpCon != null) {
 					httpCon.setRequestMethod("HEAD");
@@ -81,12 +82,16 @@ else if (code == HttpURLConnection.HTTP_NOT_FOUND) {
 						}
 					}
 				}
-				// Check content-length entry but not for JarURLConnection where
-				// this would open the jar file but effectively never close it ->
-				// for jar entries, always fall back to stream existence instead.
-				if (!(con instanceof JarURLConnection) && con.getContentLengthLong() > 0) {
+
+				if (con instanceof JarURLConnection jarCon) {
+					// For JarURLConnection, do not check content-length but rather the
+					// existence of the entry (or the jar root in case of no entryName).
+					return (jarCon.getEntryName() == null || jarCon.getJarEntry() != null);
+				}
+				else if (con.getContentLengthLong() > 0) {
 					return true;
 				}
+
 				if (httpCon != null) {
 					// No HTTP OK status, and no content-length header: give up
 					httpCon.disconnect();
@@ -346,8 +351,8 @@ public long lastModified() throws IOException {
 	 */
 	protected void customizeConnection(URLConnection con) throws IOException {
 		ResourceUtils.useCachesIfNecessary(con);
-		if (con instanceof HttpURLConnection httpConn) {
-			customizeConnection(httpConn);
+		if (con instanceof HttpURLConnection httpCon) {
+			customizeConnection(httpCon);
 		}
 	}
 

spring-core/src/main/java/org/springframework/core/io/UrlResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -234,8 +234,8 @@ public InputStream getInputStream() throws IOException {
 		}
 		catch (IOException ex) {
 			// Close the HTTP connection (if applicable).
-			if (con instanceof HttpURLConnection httpConn) {
-				httpConn.disconnect();
+			if (con instanceof HttpURLConnection httpCon) {
+				httpCon.disconnect();
 			}
 			throw ex;
 		}

spring-core/src/test/java/org/springframework/core/io/support/PathMatchingResourcePatternResolverTests.java

@@ -51,8 +51,10 @@
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.FileSystemUtils;
+import org.springframework.util.ResourceUtils;
 import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 
@@ -133,6 +135,7 @@ void encodedHashtagInPath() throws IOException {
 			assertExactFilenames("classpath*:scanned/*.txt", "resource#test1.txt", "resource#test2.txt");
 		}
 
+
 		@Nested
 		class WithHashtagsInTheirFilenames {
 
@@ -299,6 +302,7 @@ void rootPatternRetrievalInJarFiles() throws IOException {
 		}
 	}
 
+
 	@Nested
 	class ClassPathManifestEntries {
 
@@ -313,8 +317,8 @@ void javaDashJarFindsClassPathManifestEntries() throws Exception {
 			writeApplicationJar(this.temp.resolve("app.jar"));
 			String java = ProcessHandle.current().info().command().get();
 			Process process = new ProcessBuilder(java, "-jar", "app.jar")
-				.directory(this.temp.toFile())
-				.start();
+					.directory(this.temp.toFile())
+					.start();
 			assertThat(process.waitFor()).isZero();
 			String result = StreamUtils.copyToString(process.getInputStream(), StandardCharsets.UTF_8);
 			assertThat(result.replace("\\", "/")).contains("!!!!").contains("/lib/asset.jar!/assets/file.txt");
@@ -328,6 +332,8 @@ private void writeAssetJar(Path path) throws Exception {
 				StreamUtils.copy("test", StandardCharsets.UTF_8, jar);
 				jar.closeEntry();
 			}
+			assertThat(new FileSystemResource(path).exists()).isTrue();
+			assertThat(new UrlResource(ResourceUtils.JAR_URL_PREFIX + ResourceUtils.FILE_URL_PREFIX + path + ResourceUtils.JAR_URL_SEPARATOR).exists()).isTrue();
 		}
 
 		private void writeApplicationJar(Path path) throws Exception {
@@ -338,8 +344,7 @@ private void writeApplicationJar(Path path) throws Exception {
 			mainAttributes.put(Name.MANIFEST_VERSION, "1.0");
 			try (JarOutputStream jar = new JarOutputStream(new FileOutputStream(path.toFile()), manifest)) {
 				String appClassResource = ClassUtils.convertClassNameToResourcePath(
-						ClassPathManifestEntriesTestApplication.class.getName())
-						+ ClassUtils.CLASS_FILE_SUFFIX;
+						ClassPathManifestEntriesTestApplication.class.getName()) + ClassUtils.CLASS_FILE_SUFFIX;
 				String folder = "";
 				for (String name : appClassResource.split("/")) {
 					if (!name.endsWith(ClassUtils.CLASS_FILE_SUFFIX)) {
@@ -356,18 +361,19 @@ private void writeApplicationJar(Path path) throws Exception {
 					}
 				}
 			}
+			assertThat(new FileSystemResource(path).exists()).isTrue();
+			assertThat(new UrlResource(ResourceUtils.JAR_URL_PREFIX + ResourceUtils.FILE_URL_PREFIX + path + ResourceUtils.JAR_URL_SEPARATOR).exists()).isTrue();
 		}
 
 		private String buildSpringClassPath() throws Exception {
-			return copyClasses(PathMatchingResourcePatternResolver.class, "spring-core")
-					+ copyClasses(LogFactory.class, "commons-logging");
+			return copyClasses(PathMatchingResourcePatternResolver.class, "spring-core") +
+					copyClasses(LogFactory.class, "commons-logging");
 		}
 
-		private String copyClasses(Class<?> sourceClass, String destinationName)
-				throws URISyntaxException, IOException {
+		private String copyClasses(Class<?> sourceClass, String destinationName) throws URISyntaxException, IOException {
 			Path destination = this.temp.resolve(destinationName);
-			String resourcePath = ClassUtils.convertClassNameToResourcePath(sourceClass.getName())
-					+ ClassUtils.CLASS_FILE_SUFFIX;
+			String resourcePath = ClassUtils.convertClassNameToResourcePath(
+					sourceClass.getName()) + ClassUtils.CLASS_FILE_SUFFIX;
 			URL resource = getClass().getClassLoader().getResource(resourcePath);
 			URL url = new URL(resource.toString().replace(resourcePath, ""));
 			URLConnection connection = url.openConnection();
@@ -393,7 +399,6 @@ private String copyClasses(Class<?> sourceClass, String destinationName)
 			}
 			return destinationName + "/ ";
 		}
-
 	}