diff --git a/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitBlockPos.java b/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitBlockPos.java
index 72e3a7c..b88177b 100644
--- a/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitBlockPos.java
+++ b/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitBlockPos.java
@@ -50,7 +50,7 @@ public class BukkitBlockPos extends BallBlockPos {
         );
     }
 
-    public static BukkitBlockPos fromJson(String json) {
+    public static BukkitBlockPos fromJson(@NotNull String json) {
         return CoreAPI.getInstance().getGson().fromJson(json, BukkitBlockPos.class);
     }
 
diff --git a/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitLocation.java b/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitLocation.java
index 771ee95..e97eb78 100644
--- a/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitLocation.java
+++ b/ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/data/BukkitLocation.java
@@ -52,7 +52,7 @@ public class BukkitLocation extends BallLocation {
         );
     }
 
-    public static BukkitLocation fromJson(String json) {
+    public static BukkitLocation fromJson(@NotNull String json) {
         return CoreAPI.getInstance().getGson().fromJson(json, BukkitLocation.class);
     }