diff --git a/shiroha-server/src/main/java/io/nanachiyo0721/shiroha/utils/ClassScanUtil.java b/shiroha-server/src/main/java/io/nanachiyo0721/shiroha/utils/ClassScanUtil.java
index a31dab5..5f72a75 100644
--- a/shiroha-server/src/main/java/io/nanachiyo0721/shiroha/utils/ClassScanUtil.java
+++ b/shiroha-server/src/main/java/io/nanachiyo0721/shiroha/utils/ClassScanUtil.java
@@ -17,7 +17,7 @@ import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 
 public class ClassScanUtil {
-    public static @NotNull Collection<Class<?>> scanClassesUnder(String packag3, ClassLoader loader) {
+    public static @NotNull Collection<Class<?>> scanClassesUnder(@NonNull String packag3, @NonNull ClassLoader loader) {
         Set<Class<?>> classes = new HashSet<>();
         String packageDirName = packag3.replace('.', '/');
         Enumeration<URL> dirs;