Use final.
diff --git a/src/main/java/org/apache/commons/configuration2/PropertiesConfiguration.java b/src/main/java/org/apache/commons/configuration2/PropertiesConfiguration.java
index 5d5c882..8df6738 100644
--- a/src/main/java/org/apache/commons/configuration2/PropertiesConfiguration.java
+++ b/src/main/java/org/apache/commons/configuration2/PropertiesConfiguration.java
@@ -1094,7 +1094,7 @@
          */
         public void writeProperty(final String key, final List<?> values) throws IOException
         {
-            for (Object value : values) {
+            for (final Object value : values) {
                 writeProperty(key, value);
             }
         }