diff --git a/src/org/ntlab/deltaExtractor/Alias.java b/src/org/ntlab/deltaExtractor/Alias.java
index 9cc13fd..39edc86 100644
--- a/src/org/ntlab/deltaExtractor/Alias.java
+++ b/src/org/ntlab/deltaExtractor/Alias.java
@@ -70,6 +70,9 @@
 	 * @return
 	 */
 	public long getTimeStamp() {
+		if (!occurrencePoint.isValid()) {
+			return occurrencePoint.getMethodExecution().getEntryTime();
+		}
 		long stTimeStamp = occurrencePoint.getStatement().getTimeStamp();
 		Statement st = occurrencePoint.getStatement();
 		if (aliasType == AliasType.RETURN_VALUE) {