--- a/langtools/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AbstractModuleIndexWriter.java	Fri May 12 06:42:37 2017 +0200
+++ b/langtools/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AbstractModuleIndexWriter.java	Fri May 12 18:05:40 2017 -0700
@@ -25,6 +25,7 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
+import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
 import java.util.SortedMap;
@@ -101,7 +102,7 @@
      * @param tableSummary summary for the table
      * @param body the document tree to which the modules list will be added
      */
-    protected abstract void addModulesList(Map<ModuleElement, Set<PackageElement>> modules, String text,
+    protected abstract void addModulesList(Collection<ModuleElement> modules, String text,
             String tableSummary, Content body);
 
     /**
@@ -173,7 +174,7 @@
      * @param body the document tree to which the index will be added
      */
     protected void addIndex(Content body) {
-        addIndexContents(modules, "doclet.Module_Summary",
+        addIndexContents(configuration.modules, "doclet.Module_Summary",
                 configuration.getText("doclet.Member_Table_Summary",
                 configuration.getText("doclet.Module_Summary"),
                 configuration.getText("doclet.modules")), body);
@@ -201,7 +202,7 @@
      * @param tableSummary summary for the table
      * @param body the document tree to which the index contents will be added
      */
-    protected void addIndexContents(Map<ModuleElement, Set<PackageElement>> modules, String text,
+    protected void addIndexContents(Collection<ModuleElement> modules, String text,
             String tableSummary, Content body) {
         HtmlTree htmlTree = (configuration.allowTag(HtmlTag.NAV))
                 ? HtmlTree.NAV()