diff --git a/apache-commons/src/main/java/org/apache/tamaya/commons/CommonsConfigConfigSource.java b/apache-commons/src/main/java/org/apache/tamaya/commons/CommonsConfigConfigSource.java
index f2f4f55..70bb43d 100644
--- a/apache-commons/src/main/java/org/apache/tamaya/commons/CommonsConfigConfigSource.java
+++ b/apache-commons/src/main/java/org/apache/tamaya/commons/CommonsConfigConfigSource.java
@@ -39,7 +39,7 @@
     }
 
     public CommonsConfigConfigSource(String name, Configuration commonsConfig) {
-        commonsConfig = Objects.requireNonNull(commonsConfig);
+        this.commonsConfig = Objects.requireNonNull(commonsConfig);
         this.name = Objects.requireNonNull(name);
         try {
             this.ordinal = commonsConfig.getInt(ConfigSource.CONFIG_ORDINAL);