Index: trunk/autoquest-core-usageprofiles/src/main/java/de/ugoe/cs/autoquest/usageprofiles/SymbolComparator.java
===================================================================
--- trunk/autoquest-core-usageprofiles/src/main/java/de/ugoe/cs/autoquest/usageprofiles/SymbolComparator.java	(revision 1118)
+++ trunk/autoquest-core-usageprofiles/src/main/java/de/ugoe/cs/autoquest/usageprofiles/SymbolComparator.java	(revision 1182)
@@ -15,4 +15,6 @@
 package de.ugoe.cs.autoquest.usageprofiles;
 
+import java.io.Serializable;
+
 /**
  * <p>
@@ -22,5 +24,5 @@
  * @author Patrick Harms
  */
-public interface SymbolComparator<T> {
+public interface SymbolComparator<T> extends Serializable {
     
     /**