private void registerListener() {
        PluginManager pluginManager = getServer().getPluginManager();
        try {
            for (ClassPath.ClassInfo classInfo : ClassPath.from(getClassLoader())
                    .getTopLevelClasses("[PLUGIN-PACKAGE].listeners")) {
                @SuppressWarnings("rawtypes")
                Class clazz = Class.forName(classInfo.getName());
                if (Listener.class.isAssignableFrom(clazz)) {
                    pluginManager.registerEvents((Listener) clazz.newInstance(), this);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }