--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ClassWriterImpl.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ClassWriterImpl.java	Tue Apr 30 11:58:30 2019 +0530
@@ -40,7 +40,9 @@
 import javax.lang.model.util.SimpleElementVisitor8;
 
 import com.sun.source.doctree.DocTree;
+import jdk.javadoc.internal.doclets.formats.html.markup.ContentBuilder;
 import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
+import jdk.javadoc.internal.doclets.formats.html.markup.HtmlAttr;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -295,26 +297,17 @@
      */
     private Content getClassInheritenceTree(TypeMirror type) {
         TypeMirror sup;
-        HtmlTree classTreeUl = new HtmlTree(HtmlTag.UL);
-        classTreeUl.setStyle(HtmlStyle.inheritance);
-        Content liTree = null;
+        HtmlTree classTree = null;
         do {
             sup = utils.getFirstVisibleSuperClass(type);
-            if (sup != null) {
-                HtmlTree ul = new HtmlTree(HtmlTag.UL);
-                ul.setStyle(HtmlStyle.inheritance);
-                ul.add(getTreeForClassHelper(type));
-                if (liTree != null)
-                    ul.add(liTree);
-                Content li = HtmlTree.LI(ul);
-                liTree = li;
-                type = sup;
-            } else
-                classTreeUl.add(getTreeForClassHelper(type));
+            HtmlTree htmlElement = HtmlTree.DIV(HtmlStyle.inheritance, getTreeForClassHelper(type));
+            if (classTree != null)
+                htmlElement.add(classTree);
+            classTree = htmlElement;
+            type = sup;
         } while (sup != null);
-        if (liTree != null)
-            classTreeUl.add(liTree);
-        return classTreeUl;
+        classTree.put(HtmlAttr.TITLE, contents.getContent("doclet.Inheritance_Tree").toString());
+        return classTree;
     }
 
     /**
@@ -324,25 +317,25 @@
      * @return a content tree for class helper
      */
     private Content getTreeForClassHelper(TypeMirror type) {
-        Content li = new HtmlTree(HtmlTag.LI);
+        Content content = new ContentBuilder();
         if (type.equals(typeElement.asType())) {
             Content typeParameters = getTypeParameterLinks(
                     new LinkInfoImpl(configuration, LinkInfoImpl.Kind.TREE,
                     typeElement));
             if (configuration.shouldExcludeQualifier(utils.containingPackage(typeElement).toString())) {
-                li.add(utils.asTypeElement(type).getSimpleName());
-                li.add(typeParameters);
+                content.add(utils.asTypeElement(type).getSimpleName());
+                content.add(typeParameters);
             } else {
-                li.add(utils.asTypeElement(type).getQualifiedName());
-                li.add(typeParameters);
+                content.add(utils.asTypeElement(type).getQualifiedName());
+                content.add(typeParameters);
             }
         } else {
             Content link = getLink(new LinkInfoImpl(configuration,
                     LinkInfoImpl.Kind.CLASS_TREE_PARENT, type)
                     .label(configuration.getClassName(utils.asTypeElement(type))));
-            li.add(link);
+            content.add(link);
         }
-        return li;
+        return content;
     }
 
     /**

--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/resources/standard.properties	Wed Apr 24 09:10:45 2019 -0700
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/resources/standard.properties	Tue Apr 30 11:58:30 2019 +0530
@@ -94,6 +94,7 @@
 doclet.Interfaces=Interfaces
 doclet.Enclosing_Class=Enclosing class:
 doclet.Enclosing_Interface=Enclosing interface:
+doclet.Inheritance_Tree=Inheritance Tree
 doclet.System_Property=System Property
 doclet.Window_Source_title=Source code
 doclet.Window_Help_title=API Help

--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/resources/stylesheet.css	Wed Apr 24 09:10:45 2019 -0700
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/resources/stylesheet.css	Tue Apr 30 11:58:30 2019 +0530
@@ -364,18 +364,12 @@
     display:inline;
     font-size:0.9em;
 }
-ul.inheritance {
+div.inheritance {
     margin:0;
     padding:0;
 }
-ul.inheritance li {
-    display:inline;
-    list-style:none;
-}
-ul.inheritance li ul.inheritance {
-    margin-left:15px;
-    padding-left:15px;
-    padding-top:1px;
+div.inheritance div.inheritance {
+    margin-left:2em;
 }
 ul.blockList, ul.blockListLast {
     margin:10px 0 10px 0;

--- a/test/langtools/jdk/javadoc/doclet/AccessAsciiArt/AccessAsciiArt.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/test/langtools/jdk/javadoc/doclet/AccessAsciiArt/AccessAsciiArt.java	Tue Apr 30 11:58:30 2019 +0530
@@ -50,10 +50,10 @@
 
         checkOutput("p1/subpkg/SSC.html", true,
                 // Test the top line of the class tree
-                "<li><a href=\"../C.html\" title=\"class in p1\">p1.C</a></li>",
+                "<div class=\"inheritance\"><a href=\"../C.html\" title=\"class in p1\">p1.C</a>",
                 // Test the second line of the class tree
-                "<li><a href=\"../SC.html\" title=\"class in p1\">p1.SC</a></li>",
+                "<div class=\"inheritance\"><a href=\"../SC.html\" title=\"class in p1\">p1.SC</a>",
                 // Test the third line of the class tree
-                "<li>p1.subpkg.SSC</li>");
+                "<div class=\"inheritance\">p1.subpkg.SSC</div>\n</div>\n</div>");
     }
 }

--- a/test/langtools/jdk/javadoc/doclet/testInterface/TestInterface.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/test/langtools/jdk/javadoc/doclet/testInterface/TestInterface.java	Tue Apr 30 11:58:30 2019 +0530
@@ -85,20 +85,11 @@
                 + "Interface</a>&lt;CE&gt;</code></dd>\n"
                 + "</dl>",
                 //Make sure Class Tree has substituted type parameters.
-                "<ul class=\"inheritance\">\n"
-                + "<li>java.lang.Object</li>\n"
-                + "<li>\n"
-                + "<ul class=\"inheritance\">\n"
-                + "<li><a href=\"Parent.html\" title=\"class in pkg\">"
-                + "pkg.Parent</a>&lt;CE&gt;</li>\n"
-                + "<li>\n"
-                + "<ul class=\"inheritance\">\n"
-                + "<li>pkg.Child&lt;CE&gt;</li>\n"
-                + "</ul>\n"
-                + "</li>\n"
-                + "</ul>\n"
-                + "</li>\n"
-                + "</ul>",
+                "<div class=\"inheritance\" title=\"Inheritance Tree\">java.lang.Object\n"
+                + "<div class=\"inheritance\"><a href=\"Parent.html\""
+                + " title=\"class in pkg\">pkg.Parent</a>&lt;CE&gt;\n"
+                + "<div class=\"inheritance\">pkg.Child&lt;CE&gt;</div>\n"
+                + "</div>\n</div>",
                 //Make sure "Specified By" has substituted type parameters.
                 "<dt><span class=\"overrideSpecifyLabel\">Specified by:</span></dt>\n"
                 + "<dd><code><a href=\"Interface.html#method()\">method</a>"

--- a/test/langtools/jdk/javadoc/doclet/testOptions/TestOptions.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/test/langtools/jdk/javadoc/doclet/testOptions/TestOptions.java	Tue Apr 30 11:58:30 2019 +0530
@@ -268,9 +268,9 @@
         checkExit(Exit.OK);
 
         checkOutput("pkg/Foo.html", true,
-                "<li>Foo</li>");
+                "<div class=\"inheritance\">Foo</div>");
         checkOutput("deprecated/Foo.html", true,
-                "<li>deprecated.Foo</li>");
+                "<div class=\"inheritance\">deprecated.Foo</div>");
 
         javadoc("-d", "out-10a",
                 "-noqualifier", "all",
@@ -279,8 +279,8 @@
         checkExit(Exit.OK);
 
         checkOutput("pkg/Foo.html", true,
-                "<li>Foo</li>");
+                "<div class=\"inheritance\">Foo</div>");
         checkOutput("deprecated/Foo.html", true,
-                "<li>Foo</li>");
+                "<div class=\"inheritance\">Foo</div>");
     }
 }

--- a/test/langtools/jdk/javadoc/doclet/testPrivateClasses/TestPrivateClasses.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/test/langtools/jdk/javadoc/doclet/testPrivateClasses/TestPrivateClasses.java	Tue Apr 30 11:58:30 2019 +0530
@@ -66,14 +66,9 @@
                 "<a href=\"#methodInheritedFromParent(int)\">"
                 + "methodInheritedFromParent</a>",
                 // private class does not show up in tree
-                "<ul class=\"inheritance\">\n"
-                + "<li>java.lang.Object</li>\n"
-                + "<li>\n"
-                + "<ul class=\"inheritance\">\n"
-                + "<li>pkg.PublicChild</li>\n"
-                + "</ul>\n"
-                + "</li>\n"
-                + "</ul>",
+                "<div class=\"inheritance\" title=\"Inheritance Tree\">java.lang.Object\n"
+                + "<div class=\"inheritance\">pkg.PublicChild</div>\n"
+                + "</div>",
                 // Method is documented as though it is declared in the inheriting method.
                 "<pre class=\"methodSignature\">public&nbsp;void&nbsp;methodInheritedFromParent&#8203;(int&nbsp;p1)",
                 "<dl>\n"

--- a/test/langtools/jdk/javadoc/doclet/testSingletonLists/TestSingletonLists.java	Wed Apr 24 09:10:45 2019 -0700
+++ b/test/langtools/jdk/javadoc/doclet/testSingletonLists/TestSingletonLists.java	Tue Apr 30 11:58:30 2019 +0530
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8219998
+ * @bug 8219998 8221991
  * @summary Eliminate inherently singleton lists
  * @library /tools/lib ../../lib
  * @modules jdk.javadoc/jdk.javadoc.internal.tool
@@ -275,10 +275,6 @@
 
                 case "ul": case "ol": case "dl":
                     counts.push(new TreeMap<>());
-                    if (!attrs.isEmpty() && attrs.containsKey("class")
-                            && attrs.containsValue("inheritance")) {
-                        inheritanceClass = true;
-                    }
                     break;
 
                 case "li": case "dd": case "dt": {
@@ -297,11 +293,7 @@
                     if (c.get("li") == 0) {
                         error(currFile, getLineNumber(), "empty list");
                     } else if (c.get("li") == 1 && fileName != null && !excludeFiles.contains(fileName)) {
-                        if (!inheritanceClass) {
-                            error(currFile, getLineNumber(), "singleton list");
-                        } else {
-                            inheritanceClass = false;
-                        }
+                        error(currFile, getLineNumber(), "singleton list");
                     }
                     break;
                 }
@@ -319,5 +311,4 @@
             }
         }
     }
-
-}
\ No newline at end of file
+}