diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/OAuth.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/OAuth.java
index c71b02216..0a8aa416a 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/OAuth.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/OAuth.java
@@ -271,7 +271,7 @@ public class OAuth {
         }
     }
 
-    private static class DeviceTokenResponse extends ErrorResponse {
+    private final static class DeviceTokenResponse extends ErrorResponse {
         @SerializedName("user_code")
         public String userCode;
 
@@ -291,7 +291,7 @@ public class OAuth {
         public int interval;
     }
 
-    private static class TokenResponse extends ErrorResponse {
+    private final static class TokenResponse extends ErrorResponse {
         @SerializedName("token_type")
         public String tokenType;
 
@@ -329,7 +329,7 @@ public class OAuth {
      * redirect URI used to obtain the authorization
      * code.","correlation_id":"??????"}
      */
-    public static class AuthorizationResponse extends ErrorResponse {
+    public final static class AuthorizationResponse extends ErrorResponse {
         @SerializedName("token_type")
         public String tokenType;
 
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/microsoft/MicrosoftService.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/microsoft/MicrosoftService.java
index b2b4b5148..c64d2b3ee 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/microsoft/MicrosoftService.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/microsoft/MicrosoftService.java
@@ -321,16 +321,16 @@ public class MicrosoftService {
         public static final long ADD_FAMILY = 2148916238L;
     }
 
-    public static class XBox400Exception extends AuthenticationException {
+    public final static class XBox400Exception extends AuthenticationException {
     }
 
-    public static class NoMinecraftJavaEditionProfileException extends AuthenticationException {
+    public final static class NoMinecraftJavaEditionProfileException extends AuthenticationException {
     }
 
-    public static class NoXuiException extends AuthenticationException {
+    public final static class NoXuiException extends AuthenticationException {
     }
 
-    private static class XBoxLiveAuthenticationResponseDisplayClaims {
+    private final static class XBoxLiveAuthenticationResponseDisplayClaims {
         List<Map<Object, Object>> xui;
     }
 
@@ -394,7 +394,7 @@ public class MicrosoftService {
         String signature;
     }
 
-    private static class MinecraftStoreResponse extends MinecraftErrorResponse {
+    private final static class MinecraftStoreResponse extends MinecraftErrorResponse {
         @SerializedName("items")
         List<MinecraftStoreResponseItem> items;
 
@@ -405,7 +405,7 @@ public class MicrosoftService {
         String keyId;
     }
 
-    public static class MinecraftProfileResponseSkin implements Validation {
+    public final static class MinecraftProfileResponseSkin implements Validation {
         public String id;
         public String state;
         public String url;
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilService.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilService.java
index 5e73f748c..edbad40a8 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilService.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilService.java
@@ -246,11 +246,11 @@ public class YggdrasilService {
         }
     }
 
-    private static class TextureResponse {
+    private final static class TextureResponse {
         public Map<TextureType, Texture> textures;
     }
 
-    private static class AuthenticationResponse extends ErrorResponse {
+    private final static class AuthenticationResponse extends ErrorResponse {
         public String accessToken;
         public String clientToken;
         public GameProfile selectedProfile;
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/download/cleanroom/CleanroomVersionList.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/download/cleanroom/CleanroomVersionList.java
index 34b2a62e3..cb5fc5c39 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/download/cleanroom/CleanroomVersionList.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/download/cleanroom/CleanroomVersionList.java
@@ -62,7 +62,7 @@ public final class CleanroomVersionList extends VersionList<CleanroomRemoteVersi
         });
     }
 
-    private static class ReleaseResult {
+    private final static class ReleaseResult {
         String name;
         String created_at;
     }