Fix issue with fast-jar loading of top-level directories

independent-projects/bootstrap/runner/src/main/java/io/quarkus/bootstrap/runner/RunnerClassLoader.java

@@ -176,6 +176,9 @@ private ClassLoadingResource[] getClassLoadingResources(final String name) {
             dirName = "";
         }
         if (!dirName.equals(name) && fullyIndexedDirectories.contains(dirName)) {
+            if (dirName.isEmpty()) {
+                return resourceDirectoryMap.get(name);
+            }
             // If we arrive here, we know that resource being queried belongs to one of the fully indexed directories
             // Had that resource existed however, it would have been present in directlyIndexedResourcesIndexMap
             return null;

integration-tests/maven/src/test/resources-filtered/projects/classic/src/main/java/org/acme/ClasspathResources.java

@@ -1,5 +1,6 @@
 package org.acme;
 
+import javax.ws.rs.QueryParam;
 import org.apache.commons.io.IOUtils;
 
 import javax.ws.rs.GET;
@@ -32,6 +33,7 @@ public String readClassPathResources() {
                 () -> assertCorrectExactFileLocation(),
                 () -> assertInvalidDirectory(),
                 () -> assertCorrectDirectory(),
+                () -> assertTopLevelDirectory(),
                 () -> assertMultiRelease()
         );
     }
@@ -160,6 +162,22 @@ private String assertCorrectDirectory() {
         }
     }
 
+    private String assertTopLevelDirectory() {
+        final String testType = "top-level-directory";
+        try {
+            Enumeration<URL> directoryEnumeration = this.getClass().getClassLoader().getResources("assets");
+            List<URL> directoryURLList = urlList(directoryEnumeration);
+            if (directoryURLList.size() != 1) {
+                return errorResult(testType, "wrong number of directory urls");
+            }
+
+            return SUCCESS;
+        } catch (Exception e) {
+            e.printStackTrace();
+            return errorResult(testType, "exception during resolution of resource");
+        }
+    }
+
     private List<URL> urlList(Enumeration<URL> enumeration) {
         if (enumeration == null) {
             return Collections.emptyList();