javadoc change.
diff --git a/src/org/apache/xml/serializer/ElemContext.java b/src/org/apache/xml/serializer/ElemContext.java
index 755b8fa..313fe08 100644
--- a/src/org/apache/xml/serializer/ElemContext.java
+++ b/src/org/apache/xml/serializer/ElemContext.java
@@ -72,6 +72,9 @@
 
     /**
      * The URI of the element.
+     * If this value is null it means that the URI is not yet determined
+     * for the element. Valid values are the empty string "", meaning
+     * that it is in no namespace, or a string of non-zero length.
      */
     String m_elementURI = null;