diff --git a/e-Knife/src/main/java/eknife/EKnife.java b/e-Knife/src/main/java/eknife/EKnife.java
index 180fbad85e14fc28fadac0780244871fdc903f59..88969d88d57263096b5c51b0dd989438b804fc93 100644
--- a/e-Knife/src/main/java/eknife/EKnife.java
+++ b/e-Knife/src/main/java/eknife/EKnife.java
@@ -28,6 +28,10 @@ import edg.graph.Node;
 import edg.slicing.*;
 
 import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;