diff --git a/app/src/main/java/com/hippo/Native.java b/app/src/main/java/com/hippo/Native.kt
similarity index 100%
rename from app/src/main/java/com/hippo/Native.java
rename to app/src/main/java/com/hippo/Native.kt
diff --git a/app/src/main/java/com/hippo/UriArchiveAccessor.java b/app/src/main/java/com/hippo/UriArchiveAccessor.kt
similarity index 100%
rename from app/src/main/java/com/hippo/UriArchiveAccessor.java
rename to app/src/main/java/com/hippo/UriArchiveAccessor.kt
diff --git a/app/src/main/java/com/hippo/image/Image.java b/app/src/main/java/com/hippo/image/Image.kt
similarity index 100%
rename from app/src/main/java/com/hippo/image/Image.java
rename to app/src/main/java/com/hippo/image/Image.kt
diff --git a/app/src/main/java/com/hippo/image/ImageBitmap.java b/app/src/main/java/com/hippo/image/ImageBitmap.kt
similarity index 100%
rename from app/src/main/java/com/hippo/image/ImageBitmap.java
rename to app/src/main/java/com/hippo/image/ImageBitmap.kt
diff --git a/app/src/main/java/com/hippo/image/ImageDrawable.java b/app/src/main/java/com/hippo/image/ImageDrawable.kt
similarity index 100%
rename from app/src/main/java/com/hippo/image/ImageDrawable.java
rename to app/src/main/java/com/hippo/image/ImageDrawable.kt