diff --git a/config/android-checkstyle.gradle b/config/android-checkstyle.gradle
index 29c67b19..1e5ce3ba 100644
--- a/config/android-checkstyle.gradle
+++ b/config/android-checkstyle.gradle
@@ -2,7 +2,7 @@ apply plugin: 'checkstyle'
 check.dependsOn 'checkstyle'
 
 checkstyle {
-    toolVersion = '9.0.1'
+    toolVersion = '10.12.5'
 }
 
 task checkstyle(type: Checkstyle) {
diff --git a/server/src/main/java/com/genymobile/scrcpy/AudioEncoder.java b/server/src/main/java/com/genymobile/scrcpy/AudioEncoder.java
index ad8d0422..0b59369b 100644
--- a/server/src/main/java/com/genymobile/scrcpy/AudioEncoder.java
+++ b/server/src/main/java/com/genymobile/scrcpy/AudioEncoder.java
@@ -295,7 +295,7 @@ public final class AudioEncoder implements AsyncProcessor {
         }
     }
 
-    private class EncoderCallback extends MediaCodec.Callback {
+    private final class EncoderCallback extends MediaCodec.Callback {
         @TargetApi(Build.VERSION_CODES.N)
         @Override
         public void onInputBufferAvailable(MediaCodec codec, int index) {