diff --git a/app/Services/LanguageService.php b/app/Services/LanguageService.php
index 6557d5c..b899ece 100644
--- a/app/Services/LanguageService.php
+++ b/app/Services/LanguageService.php
@@ -7,12 +7,16 @@ class LanguageService {
     private static $lang = 'id';
 
     public static function init() {
-        if (isset($_SESSION['lang'])) {
+        if (isset($_SESSION['lang']) && is_string($_SESSION['lang'])) {
             self::$lang = $_SESSION['lang'];
-        } elseif (isset($_COOKIE['lang'])) {
+        } elseif (isset($_COOKIE['lang']) && is_string($_COOKIE['lang'])) {
             self::$lang = $_COOKIE['lang'];
         }
 
+        if (!is_string(self::$lang)) {
+            self::$lang = 'id';
+        }
+
         $langFile = __DIR__ . '/../../lang/' . self::$lang . '.php';
         if (file_exists($langFile)) {
             self::$translations = require $langFile;
@@ -34,6 +38,9 @@ class LanguageService {
     }
 
     public static function setLang($lang) {
+        if (!is_string($lang)) {
+            return;
+        }
         self::$lang = $lang;
         $_SESSION['lang'] = $lang;
         setcookie('lang', $lang, time() + (86400 * 30), "/");
diff --git a/index.php b/index.php
index 4e5451a..3b53384 100644
--- a/index.php
+++ b/index.php
@@ -2,7 +2,7 @@
 
 // Autoloader
 spl_autoload_register(function ($class) {
-    $prefix = 'App\';
+    $prefix = 'App\\';
     $base_dir = __DIR__ . '/app/';
 
     $len = strlen($prefix);
@@ -86,4 +86,4 @@ $router->get('/admin/withdrawals', 'AdminController@withdrawals');
 $router->get('/admin/withdrawals/approve/:id', 'AdminController@approveWithdrawal');
 $router->get('/admin/withdrawals/reject/:id', 'AdminController@rejectWithdrawal');
 
-$router->dispatch();
\ No newline at end of file
+$router->dispatch();