private static Set<String> getClassNameFromDir(String filePath, String packageName, boolean isRecursion) {
        Set<String> className = new HashSet<String>();
        File file = new File(filePath);
        File[] files = file.listFiles();
        for (File childFile : files) {
            if (childFile.isDirectory()) {
                if (isRecursion) {
                    className.addAll(getClassNameFromDir(childFile.getPath(), packageName+"."+childFile.getName(), isRecursion));
                }
            } else {
                String fileName = childFile.getName();
                if (fileName.endsWith(".class") && !fileName.contains("$")) {
                    className.add(packageName+ "." + fileName.replace(".class", ""));
                }
            }
        }
 
        return className;
    }