diff --git a/src/main/java/ch/zhaw/ads/ListStack.java b/src/main/java/ch/zhaw/ads/ListStack.java
index c476fbb..c5d5653 100644
--- a/src/main/java/ch/zhaw/ads/ListStack.java
+++ b/src/main/java/ch/zhaw/ads/ListStack.java
@@ -6,7 +6,7 @@
  */
 package ch.zhaw.ads;
 
-public class ListStack implements CommandExecutor {
+public class ListStack<T> implements CommandExecutor {
 
     @Override
     public String execute(String command) {