diff --git a/feature/library/src/main/java/one/nem/lacerta/feature/library/DocumentAdapter.java b/feature/library/src/main/java/one/nem/lacerta/feature/library/DocumentAdapter.java
index ae187769..c9164fe2 100644
--- a/feature/library/src/main/java/one/nem/lacerta/feature/library/DocumentAdapter.java
+++ b/feature/library/src/main/java/one/nem/lacerta/feature/library/DocumentAdapter.java
@@ -16,7 +16,12 @@ public class DocumentAdapter extends RecyclerView.Adapter<DocumentAdapter.Docume
 
     private List<DocumentMeta> documentMetas;
 
+
     public DocumentAdapter(List<DocumentMeta> documentMetas) {
+        // nullの場合に例外を発生させる
+        if (documentMetas == null) {
+            throw new IllegalArgumentException("DocumentMetas list cannot be null");
+        }
         this.documentMetas = documentMetas;
     }
 
@@ -31,6 +36,11 @@ public class DocumentAdapter extends RecyclerView.Adapter<DocumentAdapter.Docume
     public void onBindViewHolder(@NonNull DocumentViewHolder holder, int position) {
         // DocumentMeta から適切な情報を取得してセット
         holder.title.setText(documentMetas.get(position).getTitle());
+
+        DocumentMeta documentMeta = documentMetas.get(position);
+        if (documentMeta != null) {
+            holder.title.setText(documentMeta.getTitle());
+        }
     }
 
     @Override
diff --git a/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryTopFragment.java b/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryTopFragment.java
index 68089c29..7eed2b35 100644
--- a/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryTopFragment.java
+++ b/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryTopFragment.java
@@ -95,12 +95,6 @@ public class LibraryTopFragment extends Fragment {
 
         Toast.makeText(getContext(), "Documents: " + Integer.toString(metas.size()), Toast.LENGTH_LONG).show();
 
-        //仮データを取得
-//        List<String> documentList = new ArrayList<>();
-//        documentList.add("Document A");
-//        documentList.add("Document B");
-//        documentList.add("Document C");
-
 // Create and set the adapter
         DocumentAdapter adapter = new DocumentAdapter(metas);
         documentRecyclerView.setAdapter(adapter);