diff --git a/app/src/main/java/org/tasks/tasklist/ItemCallback.java b/app/src/main/java/org/tasks/tasklist/ItemCallback.java
deleted file mode 100644
index 5cc90fe75..000000000
--- a/app/src/main/java/org/tasks/tasklist/ItemCallback.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package org.tasks.tasklist;
-
-import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.DiffUtil;
-import org.tasks.data.TaskContainer;
-
-class ItemCallback extends DiffUtil.ItemCallback<TaskContainer> {
-
-  @Override
-  public boolean areItemsTheSame(@NonNull TaskContainer oldItem, @NonNull TaskContainer newItem) {
-    return oldItem.getId() == newItem.getId();
-  }
-
-  @Override
-  public boolean areContentsTheSame(
-      @NonNull TaskContainer oldItem, @NonNull TaskContainer newItem) {
-    return oldItem.equals(newItem);
-  }
-}
diff --git a/app/src/main/java/org/tasks/tasklist/ItemCallback.kt b/app/src/main/java/org/tasks/tasklist/ItemCallback.kt
new file mode 100644
index 000000000..bbe411147
--- /dev/null
+++ b/app/src/main/java/org/tasks/tasklist/ItemCallback.kt
@@ -0,0 +1,10 @@
+package org.tasks.tasklist
+
+import androidx.recyclerview.widget.DiffUtil
+import org.tasks.data.TaskContainer
+
+internal class ItemCallback : DiffUtil.ItemCallback<TaskContainer>() {
+    override fun areItemsTheSame(old: TaskContainer, new: TaskContainer) = old.id == new.id
+
+    override fun areContentsTheSame(old: TaskContainer, new: TaskContainer) = old == new
+}
\ No newline at end of file
diff --git a/app/src/main/java/org/tasks/tasklist/SubtaskDiffCallback.java b/app/src/main/java/org/tasks/tasklist/SubtaskDiffCallback.java
deleted file mode 100644
index ec7f9e971..000000000
--- a/app/src/main/java/org/tasks/tasklist/SubtaskDiffCallback.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package org.tasks.tasklist;
-
-import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.DiffUtil;
-import org.tasks.data.TaskContainer;
-
-class SubtaskDiffCallback extends DiffUtil.ItemCallback<TaskContainer> {
-
-  @Override
-  public boolean areItemsTheSame(@NonNull TaskContainer oldItem, @NonNull TaskContainer newItem) {
-    return oldItem.getId() == newItem.getId();
-  }
-
-  @Override
-  public boolean areContentsTheSame(
-      @NonNull TaskContainer oldItem, @NonNull TaskContainer newItem) {
-    return oldItem.equals(newItem);
-  }
-}
diff --git a/app/src/main/java/org/tasks/tasklist/SubtasksRecyclerAdapter.java b/app/src/main/java/org/tasks/tasklist/SubtasksRecyclerAdapter.java
index dd73827b0..3c600d083 100644
--- a/app/src/main/java/org/tasks/tasklist/SubtasksRecyclerAdapter.java
+++ b/app/src/main/java/org/tasks/tasklist/SubtasksRecyclerAdapter.java
@@ -39,7 +39,7 @@ public class SubtasksRecyclerAdapter extends RecyclerView.Adapter<SubtaskViewHol
     this.callbacks = callbacks;
     differ =
         new AsyncListDiffer<>(
-            this, new AsyncDifferConfig.Builder<>(new SubtaskDiffCallback()).build());
+            this, new AsyncDifferConfig.Builder<>(new ItemCallback()).build());
     metrics = activity.getResources().getDisplayMetrics();
   }