Improve handling of absolute URLs in Class-Path manifest attribute

Closes gh-10268

Author: wilkinsona

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/ChangeableUrls.java

@@ -104,7 +104,7 @@ private static List<URL> getUrlsFromClassPathOfJarManifestIfPossible(URL url) {
 			return Collections.<URL>emptyList();
 		}
 		try {
-			return getUrlsFromManifestClassPathAttribute(jarFile);
+			return getUrlsFromManifestClassPathAttribute(url, jarFile);
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException(
@@ -126,8 +126,8 @@ private static JarFile getJarFileIfPossible(URL url) {
 		return null;
 	}
 
-	private static List<URL> getUrlsFromManifestClassPathAttribute(JarFile jarFile)
-			throws IOException {
+	private static List<URL> getUrlsFromManifestClassPathAttribute(URL jarUrl,
+			JarFile jarFile) throws IOException {
 		Manifest manifest = jarFile.getManifest();
 		if (manifest == null) {
 			return Collections.<URL>emptyList();
@@ -138,17 +138,13 @@ private static List<URL> getUrlsFromManifestClassPathAttribute(JarFile jarFile)
 			return Collections.emptyList();
 		}
 		String[] entries = StringUtils.delimitedListToStringArray(classPath, " ");
-		List<URL> urls = new ArrayList<URL>(entries.length);
-		File parent = new File(jarFile.getName()).getParentFile();
-		List<File> nonExistentEntries = new ArrayList<File>();
+		List<URL> urls = new ArrayList<>(entries.length);
+		List<URL> nonExistentEntries = new ArrayList<>();
 		for (String entry : entries) {
 			try {
-				File referenced = new File(entry);
-				if (!referenced.isAbsolute()) {
-					referenced = new File(parent, entry);
-				}
-				if (referenced.exists()) {
-					urls.add(referenced.toURI().toURL());
+				URL referenced = new URL(jarUrl, entry);
+				if (new File(referenced.getFile()).exists()) {
+					urls.add(referenced);
 				}
 				else {
 					nonExistentEntries.add(referenced);

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/ChangeableUrlsTests.java

@@ -75,11 +75,12 @@ public void skipsUrls() throws Exception {
 	@Test
 	public void urlsFromJarClassPathAreConsidered() throws Exception {
 		File relative = this.temporaryFolder.newFolder();
-		File absolute = this.temporaryFolder.newFolder();
+		File absoluteFile = this.temporaryFolder.newFolder();
+		URL absoluteUrl = this.temporaryFolder.newFolder().toURI().toURL();
 		File jarWithClassPath = makeJarFileWithUrlsInManifestClassPath(
 				"project-core/target/classes/", "project-web/target/classes/",
 				"does-not-exist/target/classes", relative.getName() + "/",
-				absolute.getAbsolutePath() + "/");
+				absoluteFile.getAbsolutePath() + "/", absoluteUrl);
 		new File(jarWithClassPath.getParentFile(), "project-core/target/classes")
 				.mkdirs();
 		new File(jarWithClassPath.getParentFile(), "project-web/target/classes").mkdirs();
@@ -89,7 +90,7 @@ public void urlsFromJarClassPathAreConsidered() throws Exception {
 		assertThat(urls.toList()).containsExactly(
 				new URL(jarWithClassPath.toURI().toURL(), "project-core/target/classes/"),
 				new URL(jarWithClassPath.toURI().toURL(), "project-web/target/classes/"),
-				relative.toURI().toURL(), absolute.toURI().toURL());
+				relative.toURI().toURL(), absoluteFile.toURI().toURL(), absoluteUrl);
 	}
 
 	private URL makeUrl(String name) throws IOException {