diff --git a/source/src/main/java/one/nem/lacerta/source/database/entity/Document.java b/source/src/main/java/one/nem/lacerta/source/database/entity/Document.java
index 090ff55b..b007d982 100644
--- a/source/src/main/java/one/nem/lacerta/source/database/entity/Document.java
+++ b/source/src/main/java/one/nem/lacerta/source/database/entity/Document.java
@@ -4,6 +4,8 @@ import androidx.room.ColumnInfo;
 import androidx.room.Entity;
 import androidx.room.PrimaryKey;
 
+import java.util.Date;
+
 @Entity(tableName = "document")
 public class Document {
     @PrimaryKey