diff --git a/src/org/ntlab/deltaExtractor/Alias.java b/src/org/ntlab/deltaExtractor/Alias.java
index f62d75a..bc33fc4 100644
--- a/src/org/ntlab/deltaExtractor/Alias.java
+++ b/src/org/ntlab/deltaExtractor/Alias.java
@@ -115,7 +115,7 @@
 			return true;
 		if (obj == null)
 			return false;
-		if (getClass() != obj.getClass())
+		if (!(obj instanceof Alias))
 			return false;
 		Alias other = (Alias) obj;
 		if (aliasType != other.aliasType)