diff --git a/db/src/main/java/com/readrops/db/dao/BaseDao.java b/db/src/main/java/com/readrops/db/dao/BaseDao.java
deleted file mode 100644
index 3eebfe1c..00000000
--- a/db/src/main/java/com/readrops/db/dao/BaseDao.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.readrops.db.dao;
-
-import androidx.room.Delete;
-import androidx.room.Insert;
-import androidx.room.Update;
-
-import java.util.List;
-
-import io.reactivex.Completable;
-import io.reactivex.Single;
-
-public interface BaseDao<T> {
-
-    @Insert
-    Single<Long> insert(T entity);
-
-    // only here for compatibility with LocalFeedRepository
-    // which hasn't been written with rxjava usage in mind
-    @Insert
-    long compatInsert(T entity);
-
-    @Insert
-    List<Long> insert(List<T> entities);
-
-    @Update
-    Completable update(T entity);
-
-    @Update
-    Completable update(List<T> entities);
-
-    @Delete
-    Completable delete(T entity);
-
-    @Delete
-    Completable delete(List<T> entities);
-}
diff --git a/db/src/main/java/com/readrops/db/dao/BaseDao.kt b/db/src/main/java/com/readrops/db/dao/BaseDao.kt
new file mode 100644
index 00000000..e070c04f
--- /dev/null
+++ b/db/src/main/java/com/readrops/db/dao/BaseDao.kt
@@ -0,0 +1,33 @@
+package com.readrops.db.dao
+
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Update
+import io.reactivex.Completable
+import io.reactivex.Single
+
+interface BaseDao<T> {
+
+    @Insert
+    fun insert(entity: T): Single<Long>
+
+    // only here for compatibility with LocalFeedRepository
+    // which hasn't been written with rxjava usage in mind
+    @Insert
+    fun compatInsert(entity: T): Long
+
+    @Insert
+    fun insert(entities: List<T>?): List<Long>
+
+    @Update
+    fun update(entity: T): Completable
+
+    @Update
+    fun update(entities: List<T>?): Completable
+
+    @Delete
+    fun delete(entity: T): Completable
+
+    @Delete
+    fun delete(entities: List<T>?): Completable
+}
\ No newline at end of file