src/java.compiler/share/classes/javax/lang/model/element/Element.java

@@ -137,11 +137,11 @@
      * <li> If this is a {@linkplain TypeElement#getEnclosingElement
      * top-level type}, its package is returned.
      *
      * <li> If this is a {@linkplain
      * PackageElement#getEnclosingElement package}, its module is
-     * returned.
+     * returned if such a module exists. Otherwise, {@code null} is returned.
      *
      * <li> If this is a {@linkplain
      * TypeParameterElement#getEnclosingElement type parameter},
      * {@linkplain TypeParameterElement#getGenericElement the
      * generic element} of the type parameter is returned.