diff --git a/poi/src/main/java/org/apache/poi/poifs/property/PropertyTable.java b/poi/src/main/java/org/apache/poi/poifs/property/PropertyTable.java
index e0142f02c3..562413e0c6 100644
--- a/poi/src/main/java/org/apache/poi/poifs/property/PropertyTable.java
+++ b/poi/src/main/java/org/apache/poi/poifs/property/PropertyTable.java
@@ -228,7 +228,7 @@ public final class PropertyTable implements BATManaged {
     }
 
     // Maximum depth of the property tree to prevent stackoverflow errors
-    private static int MAX_PROPERTY_DEPTH = 1000;
+    private static final int MAX_PROPERTY_DEPTH = 1000;
 
     private void populatePropertyTree(final DirectoryProperty root, final int depth) throws IOException {
         if (depth > MAX_PROPERTY_DEPTH) {