diff --git a/src/java/org/apache/poi/ss/usermodel/PageOrder.java b/src/java/org/apache/poi/ss/usermodel/PageOrder.java
index 341f2bf72..c3faf36b3 100644
--- a/src/java/org/apache/poi/ss/usermodel/PageOrder.java
+++ b/src/java/org/apache/poi/ss/usermodel/PageOrder.java
@@ -34,7 +34,7 @@ public enum PageOrder {
     OVER_THEN_DOWN(2);
 
 
-    private int order;
+    private final int order;
 
 
     private PageOrder(int order) {