#vulnerable code 
                             private static void getClassesFromDir(Collection<Class<?>> classes, File root, File dir, String pkg, Pattern regex,
			Predicate<Class<?>> filter, Class<? extends Annotation> annotated, ClassLoader classLoader) {
		U.must(dir.isDirectory());
		Log.debug("Traversing directory", "root", root, "dir", dir);

		for (File file : dir.listFiles()) {
			if (file.isDirectory()) {
				getClassesFromDir(classes, root, file, pkg, regex, filter, annotated, classLoader);
			} else {
				String rootPath = U.trimr(root.getAbsolutePath(), File.separatorChar);
				int from = rootPath.length() + 1;
				String relName = file.getAbsolutePath().substring(from);

				if (!ignore(relName)) {
					scanFile(classes, regex, filter, annotated, classLoader, relName);
				}
			}
		}
	} 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             private static void getClassesFromDir(Collection<Class<?>> classes, File root, File dir, String pkg, Pattern regex,
			Predicate<Class<?>> filter, Class<? extends Annotation> annotated, ClassLoader classLoader) {
		U.must(dir.isDirectory());
		Log.debug("Traversing directory", "root", root, "dir", dir);

		File[] files = dir.listFiles();
		if (files == null) {
			Log.warn("Not a folder!", "dir", dir);
			return;
		}

		for (File file : files) {
			if (file.isDirectory()) {
				getClassesFromDir(classes, root, file, pkg, regex, filter, annotated, classLoader);
			} else {
				String rootPath = U.trimr(root.getAbsolutePath(), File.separatorChar);
				int from = rootPath.length() + 1;
				String relName = file.getAbsolutePath().substring(from);

				if (!ignore(relName)) {
					scanFile(classes, regex, filter, annotated, classLoader, relName);
				}
			}
		}
	}