diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/DocPretty.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/DocPretty.java
index 37f0fe0e9c0fa..e7c65ffac4e45 100644
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/DocPretty.java
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/DocPretty.java
@@ -121,23 +121,12 @@ protected void printTagName(DocTree node) throws IOException {
     public Void visitAttribute(AttributeTree node, Void p) {
         try {
             print(node.getName());
-            String quote;
-            switch (node.getValueKind()) {
-                case EMPTY:
-                    quote = null;
-                    break;
-                case UNQUOTED:
-                    quote = "";
-                    break;
-                case SINGLE:
-                    quote = "'";
-                    break;
-                case DOUBLE:
-                    quote = "\"";
-                    break;
-                default:
-                    throw new AssertionError();
-            }
+            String quote = switch (node.getValueKind()) {
+                case EMPTY -> null;
+                case UNQUOTED -> "";
+                case SINGLE -> "'";
+                case DOUBLE -> "\"";
+            };
             if (quote != null) {
                 print("=" + quote);
                 print(node.getValue());
diff --git a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java
index e3ffdbe3a49b3..7007a160f9d59 100644
--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java
@@ -81,8 +81,6 @@ public class CommentHelper {
     public final DocCommentTree dcTree;
     public final Element element;
 
-    public static final String SPACER = " ";
-
     /**
      * Creates a utility class to encapsulate the contextual information for a doc comment tree.
      *
@@ -99,27 +97,17 @@ public CommentHelper(BaseConfiguration configuration, Element element, TreePath
     }
 
     public String getTagName(DocTree dtree) {
-        switch (dtree.getKind()) {
-            case AUTHOR:
-            case DEPRECATED:
-            case PARAM:
-            case PROVIDES:
-            case RETURN:
-            case SEE:
-            case SERIAL_DATA:
-            case SERIAL_FIELD:
-            case THROWS:
-            case UNKNOWN_BLOCK_TAG:
-            case USES:
-            case VERSION:
-                return ((BlockTagTree) dtree).getTagName();
-            case UNKNOWN_INLINE_TAG:
-                return ((InlineTagTree) dtree).getTagName();
-            case ERRONEOUS:
-                return "erroneous";
-            default:
-                return dtree.getKind().tagName;
-        }
+        return switch (dtree.getKind()) {
+            case AUTHOR, DEPRECATED, PARAM, PROVIDES, RETURN, SEE, SERIAL_DATA, SERIAL_FIELD,
+                    THROWS, UNKNOWN_BLOCK_TAG, USES, VERSION ->
+                    ((BlockTagTree) dtree).getTagName();
+            case UNKNOWN_INLINE_TAG ->
+                    ((InlineTagTree) dtree).getTagName();
+            case ERRONEOUS ->
+                    "erroneous";
+            default ->
+                    dtree.getKind().tagName;
+        };
     }
 
     public String getParameterName(ParamTree p) {
@@ -168,11 +156,6 @@ public List<? extends DocTree> getDescription(DocTree dtree) {
         return getTags(dtree);
     }
 
-    public TypeElement getReferencedClass(DocTree dtree) {
-        Element e = getReferencedElement(dtree);
-        return getReferencedClass(e);
-    }
-
     public TypeElement getReferencedClass(Element e) {
         Utils utils = configuration.utils;
         if (e == null) {
@@ -185,11 +168,6 @@ public TypeElement getReferencedClass(Element e) {
         return null;
     }
 
-    public String getReferencedModuleName(DocTree dtree) {
-        String s = getReferencedSignature(dtree);
-        return getReferencedModuleName(s);
-    }
-
     public String getReferencedModuleName(String signature) {
         if (signature == null || signature.contains("#") || signature.contains("(")) {
             return null;
@@ -219,11 +197,6 @@ public String getReferencedFragment(String signature) {
         return (n == -1) ? null : signature.substring(n + 1);
     }
 
-    public PackageElement getReferencedPackage(DocTree dtree) {
-        Element e = getReferencedElement(dtree);
-        return getReferencedPackage(e);
-    }
-
     public PackageElement getReferencedPackage(Element e) {
         if (e != null) {
             Utils utils = configuration.utils;
@@ -232,11 +205,6 @@ public PackageElement getReferencedPackage(Element e) {
         return null;
     }
 
-    public ModuleElement getReferencedModule(DocTree dtree) {
-        Element e = getReferencedElement(dtree);
-        return getReferencedModule(e);
-    }
-
     public ModuleElement getReferencedModule(Element e) {
         if (e != null && configuration.utils.isModule(e)) {
             return (ModuleElement) e;
@@ -248,10 +216,6 @@ public List<? extends DocTree> getFirstSentenceTrees(List<? extends DocTree> bod
         return configuration.docEnv.getDocTrees().getFirstSentence(body);
     }
 
-    public List<? extends DocTree> getFirstSentenceTrees(DocTree dtree) {
-        return getFirstSentenceTrees(getBody(dtree));
-    }
-
     public Element getReferencedElement(DocTree dtree) {
         return new ReferenceDocTreeVisitor<Element>() {
             @Override
@@ -388,14 +352,11 @@ public List<? extends DocTree> getReference(DocTree dtree) {
     }
 
     public IdentifierTree getName(DocTree dtree) {
-        switch (dtree.getKind()) {
-            case PARAM:
-                return ((ParamTree)dtree).getName();
-            case SERIAL_FIELD:
-                return ((SerialFieldTree)dtree).getName();
-            default:
-                return null;
-            }
+        return switch (dtree.getKind()) {
+            case PARAM -> ((ParamTree) dtree).getName();
+            case SERIAL_FIELD -> ((SerialFieldTree) dtree).getName();
+            default -> null;
+        };
     }
 
     public List<? extends DocTree> getTags(DocTree dtree) {
@@ -553,12 +514,10 @@ private DocTreePath getInheritedDocTreePath(DocTree dtree, ExecutableElement ee)
      */
     @Override
     public String toString() {
-        StringBuilder sb = new StringBuilder("CommentHelper{" + "path=" + path + ", dcTree=" + dcTree);
-        sb.append(", element=");
-        sb.append(element.getEnclosingElement());
-        sb.append("::");
-        sb.append(element);
-        sb.append('}');
-        return sb.toString();
+        return "CommentHelper{"
+                + "path=" + path
+                + ", dcTree=" + dcTree
+                + ", element=" + element.getEnclosingElement() + "::" + element
+                + '}';
     }
 }