Normalize search path in PropertiesLauncher

* Windows: allow absolute file paths without file:/// prefix
* All: only add nested archives (not directories), so loader.path=lib/*
behaves the same as -classpath=lib/* (except for adding zip files)

Fixes gh-1352

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/PropertiesLauncher.java

@@ -456,7 +456,7 @@ public class PropertiesLauncher extends Launcher {
 		String root = cleanupPath(stripFileUrlPrefix(path));
 		List<Archive> lib = new ArrayList<Archive>();
 		File file = new File(root);
-		if (!root.startsWith("/")) {
+		if (!isAbsolutePath(root)) {
 			file = new File(this.home, root);
 		}
 		if (file.isDirectory()) {
@@ -479,6 +479,11 @@ public class PropertiesLauncher extends Launcher {
 		return lib;
 	}
 
+	private boolean isAbsolutePath(String root) {
+		// Windows contains ":" others start with "/"
+		return root.contains(":") || root.startsWith("/");
+	}
+
 	private Archive getArchive(File file) throws IOException {
 		String name = file.getName().toLowerCase();
 		if (name.endsWith(".jar") || name.endsWith(".zip")) {
@@ -534,6 +539,10 @@ public class PropertiesLauncher extends Launcher {
 
 	private String cleanupPath(String path) {
 		path = path.trim();
+		// No need for current dir path
+		if (path.startsWith("./")) {
+			path = path.substring(2);
+		}
 		if (path.toLowerCase().endsWith(".jar") || path.toLowerCase().endsWith(".zip")) {
 			return path;
 		}
@@ -542,14 +551,10 @@ public class PropertiesLauncher extends Launcher {
 		}
 		else {
 			// It's a directory
-			if (!path.endsWith("/")) {
+			if (!path.endsWith("/") && !path.equals(".")) {
 				path = path + "/";
 			}
 		}
-		// No need for current dir path
-		if (path.startsWith("./")) {
-			path = path.substring(2);
-		}
 		return path;
 	}
 
@@ -593,8 +598,7 @@ public class PropertiesLauncher extends Launcher {
 
 		@Override
 		public boolean matches(Entry entry) {
-			return entry.isDirectory() || entry.getName().endsWith(DOT_JAR)
-					|| entry.getName().endsWith(DOT_ZIP);
+			return entry.getName().endsWith(DOT_JAR) || entry.getName().endsWith(DOT_ZIP);
 		}
 	}
 

spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/PropertiesLauncherTests.java

@@ -112,6 +112,17 @@ public class PropertiesLauncherTests {
 		waitFor("Hello World");
 	}
 
+	@Test
+	public void testUserSpecifiedJarPathWithDot() throws Exception {
+		System.setProperty("loader.path", "./jars/app.jar");
+		System.setProperty("loader.main", "demo.Application");
+		PropertiesLauncher launcher = new PropertiesLauncher();
+		assertEquals("[jars/app.jar]", ReflectionTestUtils.getField(launcher, "paths")
+				.toString());
+		launcher.launch(new String[0]);
+		waitFor("Hello World");
+	}
+
 	@Test
 	public void testUserSpecifiedClassLoader() throws Exception {
 		System.setProperty("loader.path", "jars/app.jar");