8222669: Create and use new html.Entity class

Reviewed-by: hannesw

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AbstractExecutableMemberWriter.java

@@ -40,12 +40,16 @@ import javax.lang.model.type.TypeVariable;
 import javax.lang.model.util.SimpleTypeVisitor9;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.util.DocletConstants;
 
-import static jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl.Kind.*;
+import static jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl.Kind.EXECUTABLE_MEMBER_PARAM;
+import static jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl.Kind.MEMBER;
+import static jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl.Kind.MEMBER_TYPE_PARAMS;
+import static jdk.javadoc.internal.doclets.formats.html.LinkInfoImpl.Kind.RECEIVER_TYPE;
 
 /**
  * Print method and constructor info.
@@ -79,7 +83,7 @@ public abstract class AbstractExecutableMemberWriter extends AbstractMemberWrite
         Content typeParameters = getTypeParameters(member);
         if (!typeParameters.isEmpty()) {
             htmltree.add(typeParameters);
-            htmltree.add(Contents.SPACE);
+            htmltree.add(Entity.NO_BREAK_SPACE);
         }
     }
 
@@ -107,7 +111,7 @@ public abstract class AbstractExecutableMemberWriter extends AbstractMemberWrite
         }
         String signature = utils.flatSignature((ExecutableElement) member);
         if (signature.length() > 2) {
-            deprecatedLinkContent.add(Contents.ZERO_WIDTH_SPACE);
+            deprecatedLinkContent.add(Entity.ZERO_WIDTH_SPACE);
         }
         deprecatedLinkContent.add(signature);
 
@@ -160,7 +164,7 @@ public abstract class AbstractExecutableMemberWriter extends AbstractMemberWrite
                 param.asType()).varargs(isVarArg));
         tree.add(link);
         if(name(param).length() > 0) {
-            tree.add(Contents.SPACE);
+            tree.add(Entity.NO_BREAK_SPACE);
             tree.add(name(param));
         }
     }
@@ -176,11 +180,11 @@ public abstract class AbstractExecutableMemberWriter extends AbstractMemberWrite
     protected void addReceiverAnnotations(ExecutableElement member, TypeMirror rcvrType,
             List<? extends AnnotationMirror> annotationMirrors, Content tree) {
         writer.addReceiverAnnotationInfo(member, rcvrType, annotationMirrors, tree);
-        tree.add(Contents.SPACE);
+        tree.add(Entity.NO_BREAK_SPACE);
         tree.add(utils.getTypeName(rcvrType, false));
         LinkInfoImpl linkInfo = new LinkInfoImpl(configuration, RECEIVER_TYPE, rcvrType);
         tree.add(writer.getTypeParameterLinks(linkInfo));
-        tree.add(Contents.SPACE);
+        tree.add(Entity.NO_BREAK_SPACE);
         tree.add("this");
     }
 
@@ -254,7 +258,7 @@ public abstract class AbstractExecutableMemberWriter extends AbstractMemberWrite
         if (paramTree.isEmpty()) {
             htmltree.add("()");
         } else {
-            htmltree.add(Contents.ZERO_WIDTH_SPACE);
+            htmltree.add(Entity.ZERO_WIDTH_SPACE);
             htmltree.add("(");
             htmltree.add(paramTree);
             paramTree.add(")");

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AbstractIndexWriter.java

@@ -25,9 +25,13 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import java.io.*;
+import java.io.IOException;
-import java.util.*;
+import java.io.OutputStream;
-import java.util.zip.*;
+import java.io.Writer;
+import java.util.Collection;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
 
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
@@ -37,6 +41,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.util.SimpleElementVisitor9;
 
 import com.sun.source.doctree.DocTree;
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -338,7 +343,7 @@ public class AbstractIndexWriter extends HtmlDocletWriter {
         dlTree.add(dt);
         Content dd = new HtmlTree(HtmlTag.DD);
         if (sii.getDescription().isEmpty()) {
-            dd.add(Contents.SPACE);
+            dd.add(Entity.NO_BREAK_SPACE);
         } else {
             dd.add(sii.getDescription());
         }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AbstractMemberWriter.java

@@ -25,10 +25,10 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import java.util.ArrayList;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
+import java.util.List;
-
+import java.util.Set;
-import java.util.*;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
 import javax.lang.model.element.Element;
@@ -39,18 +39,26 @@ import javax.lang.model.element.TypeParameterElement;
 import javax.lang.model.type.TypeMirror;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.formats.html.markup.Links;
+import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.MemberSummaryWriter;
 import jdk.javadoc.internal.doclets.toolkit.Resources;
 import jdk.javadoc.internal.doclets.toolkit.taglets.DeprecatedTaglet;
 import jdk.javadoc.internal.doclets.toolkit.util.Utils;
 
-import static javax.lang.model.element.Modifier.*;
+import static javax.lang.model.element.Modifier.ABSTRACT;
+import static javax.lang.model.element.Modifier.NATIVE;
+import static javax.lang.model.element.Modifier.PUBLIC;
+import static javax.lang.model.element.Modifier.STRICTFP;
+import static javax.lang.model.element.Modifier.SYNCHRONIZED;
 
 /**
  * The base class for member writers.
@@ -256,7 +264,7 @@ public abstract class AbstractMemberWriter implements MemberSummaryWriter {
         if (!set.isEmpty()) {
             String mods = set.stream().map(Modifier::toString).collect(Collectors.joining(" "));
             htmltree.add(mods);
-            htmltree.add(Contents.SPACE);
+            htmltree.add(Entity.NO_BREAK_SPACE);
         }
     }
 
@@ -284,7 +292,7 @@ public abstract class AbstractMemberWriter implements MemberSummaryWriter {
         addModifier(member, code);
         if (type == null) {
             code.add(utils.isClass(member) ? "class" : "interface");
-            code.add(Contents.SPACE);
+            code.add(Entity.NO_BREAK_SPACE);
         } else {
             List<? extends TypeParameterElement> list = utils.isExecutableElement(member)
                     ? ((ExecutableElement)member).getTypeParameters()
@@ -297,7 +305,7 @@ public abstract class AbstractMemberWriter implements MemberSummaryWriter {
                 if (typeParameters.charCount() > 10) {
                     code.add(new HtmlTree(HtmlTag.BR));
                 } else {
-                    code.add(Contents.SPACE);
+                    code.add(Entity.NO_BREAK_SPACE);
                 }
                 code.add(
                         writer.getLink(new LinkInfoImpl(configuration,

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AnnotationTypeFieldWriterImpl.java

@@ -31,6 +31,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.type.TypeMirror;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -138,7 +139,7 @@ public class AnnotationTypeFieldWriterImpl extends AbstractMemberWriter
                 writer.getLink(new LinkInfoImpl(configuration,
                         LinkInfoImpl.Kind.MEMBER, getType(member)));
         pre.add(link);
-        pre.add(Contents.SPACE);
+        pre.add(Entity.NO_BREAK_SPACE);
         if (configuration.linksource) {
             Content memberName = new StringContent(name(member));
             writer.addSrcLink(member, memberName, pre);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AnnotationTypeRequiredMemberWriterImpl.java

@@ -31,6 +31,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.type.TypeMirror;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -142,7 +143,7 @@ public class AnnotationTypeRequiredMemberWriterImpl extends AbstractMemberWriter
                 writer.getLink(new LinkInfoImpl(configuration,
                         LinkInfoImpl.Kind.MEMBER, getType(member)));
         pre.add(link);
-        pre.add(Contents.SPACE);
+        pre.add(Entity.NO_BREAK_SPACE);
         if (configuration.linksource) {
             Content memberName = new StringContent(name(member));
             writer.addSrcLink(member, memberName, pre);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/AnnotationTypeWriterImpl.java

@@ -32,6 +32,7 @@ import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
 
 import com.sun.source.doctree.DocTree;
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -101,7 +102,7 @@ public class AnnotationTypeWriterImpl extends SubWriterHolderWriter
             ModuleElement mdle = configuration.docEnv.getElementUtils().getModuleOf(annotationType);
             Content typeModuleLabel = HtmlTree.SPAN(HtmlStyle.moduleLabelInType, contents.moduleLabel);
             Content moduleNameDiv = HtmlTree.DIV(HtmlStyle.subTitle, typeModuleLabel);
-            moduleNameDiv.add(Contents.SPACE);
+            moduleNameDiv.add(Entity.NO_BREAK_SPACE);
             moduleNameDiv.add(getModuleLink(mdle, new StringContent(mdle.getQualifiedName())));
             div.add(moduleNameDiv);
         }
@@ -109,7 +110,7 @@ public class AnnotationTypeWriterImpl extends SubWriterHolderWriter
         if (!pkg.isUnnamed()) {
             Content typePackageLabel = HtmlTree.SPAN(HtmlStyle.packageLabelInType, contents.packageLabel);
             Content pkgNameDiv = HtmlTree.DIV(HtmlStyle.subTitle, typePackageLabel);
-            pkgNameDiv.add(Contents.SPACE);
+            pkgNameDiv.add(Entity.NO_BREAK_SPACE);
             Content pkgNameContent = getPackageLink(pkg, new StringContent(utils.getPackageName(pkg)));
             pkgNameDiv.add(pkgNameContent);
             div.add(pkgNameDiv);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ClassWriterImpl.java

@@ -25,7 +25,11 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import java.util.*;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.Element;
@@ -36,6 +40,7 @@ import javax.lang.model.type.TypeMirror;
 import javax.lang.model.util.SimpleElementVisitor8;
 
 import com.sun.source.doctree.DocTree;
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -122,7 +127,7 @@ public class ClassWriterImpl extends SubWriterHolderWriter implements ClassWrite
             ModuleElement mdle = configuration.docEnv.getElementUtils().getModuleOf(typeElement);
             Content classModuleLabel = HtmlTree.SPAN(HtmlStyle.moduleLabelInType, contents.moduleLabel);
             Content moduleNameDiv = HtmlTree.DIV(HtmlStyle.subTitle, classModuleLabel);
-            moduleNameDiv.add(Contents.SPACE);
+            moduleNameDiv.add(Entity.NO_BREAK_SPACE);
             moduleNameDiv.add(getModuleLink(mdle,
                     new StringContent(mdle.getQualifiedName())));
             div.add(moduleNameDiv);
@@ -131,7 +136,7 @@ public class ClassWriterImpl extends SubWriterHolderWriter implements ClassWrite
         if (!pkg.isUnnamed()) {
             Content classPackageLabel = HtmlTree.SPAN(HtmlStyle.packageLabelInType, contents.packageLabel);
             Content pkgNameDiv = HtmlTree.DIV(HtmlStyle.subTitle, classPackageLabel);
-            pkgNameDiv.add(Contents.SPACE);
+            pkgNameDiv.add(Entity.NO_BREAK_SPACE);
             Content pkgNameContent = getPackageLink(pkg,
                     new StringContent(utils.getPackageName(pkg)));
             pkgNameDiv.add(pkgNameContent);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ConstantsSummaryWriterImpl.java

@@ -25,10 +25,8 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import java.util.Collection;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
+import java.util.Set;
-
-import java.util.*;
 
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.PackageElement;
@@ -36,12 +34,15 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation.PageMode;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
+import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.ConstantsSummaryWriter;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.util.DocFileIOException;
@@ -265,7 +266,7 @@ public class ConstantsSummaryWriterImpl extends HtmlDocletWriter implements Cons
         for (Modifier mod : member.getModifiers()) {
             Content modifier = new StringContent(mod.toString());
             code.add(modifier);
-            code.add(Contents.SPACE);
+            code.add(Entity.NO_BREAK_SPACE);
         }
         Content type = getLink(new LinkInfoImpl(configuration,
                 LinkInfoImpl.Kind.CONSTANT_SUMMARY, member.asType()));

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ConstructorWriterImpl.java

@@ -33,6 +33,7 @@ import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -297,7 +298,7 @@ public class ConstructorWriterImpl extends AbstractExecutableMemberWriter
             } else if (utils.isPrivate(member)) {
                 code.add("private ");
             } else if (utils.isPublic(member)) {
-                code.add(Contents.SPACE);
+                code.add(Entity.NO_BREAK_SPACE);
             } else {
                 code.add(
                         resources.getText("doclet.Package_private"));

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/Contents.java

@@ -32,8 +32,8 @@ import java.util.regex.Pattern;
 
 import jdk.javadoc.internal.doclets.formats.html.markup.Comment;
 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.FixedStringContent;
-import jdk.javadoc.internal.doclets.formats.html.markup.RawHtml;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.Resources;
@@ -52,8 +52,6 @@ import jdk.javadoc.internal.doclets.toolkit.util.VisibleMemberTable;
  * only created once per doclet-instance, instead of once per generated page.
  */
 public class Contents {
-    public static final Content SPACE = RawHtml.nbsp;
-    public static final Content ZERO_WIDTH_SPACE = RawHtml.zws;
 
     public final Content allClassesLabel;
     public final Content allImplementedInterfacesLabel;
@@ -400,7 +398,7 @@ public class Contents {
         int p;
         while ((p = text.indexOf(" ", start)) != -1) {
             c.add(text.substring(start, p));
-            c.add(RawHtml.nbsp);
+            c.add(Entity.NO_BREAK_SPACE);
             start = p + 1;
         }
         c.add(text.substring(start));

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/FieldWriterImpl.java

@@ -33,6 +33,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -248,7 +249,7 @@ public class FieldWriterImpl extends AbstractMemberWriter
         }
         Content labelHeading = HtmlTree.HEADING(Headings.TypeDeclaration.INHERITED_SUMMARY_HEADING,
                 label);
-        labelHeading.add(Contents.SPACE);
+        labelHeading.add(Entity.NO_BREAK_SPACE);
         labelHeading.add(classLink);
         inheritedTree.add(labelHeading);
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDocletWriter.java

@@ -25,11 +25,13 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Head;
+import java.util.ArrayList;
-import jdk.javadoc.internal.doclets.formats.html.markup.HtmlAttr;
+import java.util.LinkedList;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
+import java.util.List;
-
+import java.util.ListIterator;
-import java.util.*;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -69,8 +71,10 @@ import com.sun.source.doctree.SummaryTree;
 import com.sun.source.doctree.SystemPropertyTree;
 import com.sun.source.doctree.TextTree;
 import com.sun.source.util.SimpleDocTreeVisitor;
-
 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.Head;
+import jdk.javadoc.internal.doclets.formats.html.markup.HtmlAttr;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlDocument;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
@@ -79,6 +83,7 @@ import jdk.javadoc.internal.doclets.formats.html.markup.Links;
 import jdk.javadoc.internal.doclets.formats.html.markup.RawHtml;
 import jdk.javadoc.internal.doclets.formats.html.markup.Script;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.AnnotationTypeWriter;
 import jdk.javadoc.internal.doclets.toolkit.ClassWriter;
 import jdk.javadoc.internal.doclets.toolkit.Content;
@@ -97,7 +102,12 @@ import jdk.javadoc.internal.doclets.toolkit.util.DocletConstants;
 import jdk.javadoc.internal.doclets.toolkit.util.Utils;
 import jdk.javadoc.internal.doclets.toolkit.util.VisibleMemberTable;
 
-import static com.sun.source.doctree.DocTree.Kind.*;
+import static com.sun.source.doctree.DocTree.Kind.CODE;
+import static com.sun.source.doctree.DocTree.Kind.COMMENT;
+import static com.sun.source.doctree.DocTree.Kind.LINK;
+import static com.sun.source.doctree.DocTree.Kind.LINK_PLAIN;
+import static com.sun.source.doctree.DocTree.Kind.SEE;
+import static com.sun.source.doctree.DocTree.Kind.TEXT;
 import static jdk.javadoc.internal.doclets.toolkit.util.CommentHelper.SPACER;
 
 
@@ -502,7 +512,7 @@ public class HtmlDocletWriter {
      */
     public Content getTableCaption(Content title) {
         Content captionSpan = HtmlTree.SPAN(title);
-        Content space = Contents.SPACE;
+        Content space = Entity.NO_BREAK_SPACE;
         Content tabSpan = HtmlTree.SPAN(HtmlStyle.tabEnd, space);
         Content caption = HtmlTree.CAPTION(captionSpan);
         caption.add(tabSpan);
@@ -1226,7 +1236,7 @@ public class HtmlDocletWriter {
             htmltree.add(div);
         }
         if (tags.isEmpty()) {
-            htmltree.add(Contents.SPACE);
+            htmltree.add(Entity.NO_BREAK_SPACE);
         }
     }
 

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/LinkFactoryImpl.java

@@ -35,6 +35,7 @@ import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.TypeMirror;
 
 import jdk.javadoc.internal.doclets.formats.html.markup.ContentBuilder;
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 import jdk.javadoc.internal.doclets.toolkit.BaseConfiguration;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.Resources;
@@ -162,7 +163,7 @@ public class LinkFactoryImpl extends LinkFactory {
             for (TypeMirror t : vars) {
                 if (many) {
                     links.add(",");
-                    links.add(Contents.ZERO_WIDTH_SPACE);
+                    links.add(Entity.ZERO_WIDTH_SPACE);
                 }
                 links.add(getTypeParameterLink(linkInfo, t));
                 many = true;

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/MethodWriterImpl.java

@@ -34,6 +34,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.type.TypeMirror;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -190,7 +191,7 @@ public class MethodWriterImpl extends AbstractExecutableMemberWriter
                         utils.isClass(holder)
                                 ? contents.descfrmClassLabel
                                 : contents.descfrmInterfaceLabel);
-                descfrmLabel.add(Contents.SPACE);
+                descfrmLabel.add(Entity.NO_BREAK_SPACE);
                 descfrmLabel.add(codelLink);
                 methodDocTree.add(HtmlTree.DIV(HtmlStyle.block, descfrmLabel));
                 writer.addInlineComment(method, methodDocTree);
@@ -297,7 +298,7 @@ public class MethodWriterImpl extends AbstractExecutableMemberWriter
         }
         Content labelHeading = HtmlTree.HEADING(Headings.TypeDeclaration.INHERITED_SUMMARY_HEADING,
                 label);
-        labelHeading.add(Contents.SPACE);
+        labelHeading.add(Entity.NO_BREAK_SPACE);
         labelHeading.add(classLink);
         inheritedTree.add(labelHeading);
     }
@@ -353,9 +354,9 @@ public class MethodWriterImpl extends AbstractExecutableMemberWriter
                     .where(writer.links.getName(writer.getAnchor(method))).label(method.getSimpleName()));
             Content codeMethLink = HtmlTree.CODE(methlink);
             Content dd = HtmlTree.DD(codeMethLink);
-            dd.add(Contents.SPACE);
+            dd.add(Entity.NO_BREAK_SPACE);
             dd.add(writer.contents.inClass);
-            dd.add(Contents.SPACE);
+            dd.add(Entity.NO_BREAK_SPACE);
             dd.add(codeOverridenTypeLink);
             dl.add(dd);
         }
@@ -389,9 +390,9 @@ public class MethodWriterImpl extends AbstractExecutableMemberWriter
                     implementedMeth.getSimpleName(), false);
             Content codeMethLink = HtmlTree.CODE(methlink);
             Content dd = HtmlTree.DD(codeMethLink);
-            dd.add(Contents.SPACE);
+            dd.add(Entity.NO_BREAK_SPACE);
             dd.add(contents.inInterface);
-            dd.add(Contents.SPACE);
+            dd.add(Entity.NO_BREAK_SPACE);
             dd.add(codeIntfacLink);
             dl.add(dd);
         }
@@ -409,7 +410,7 @@ public class MethodWriterImpl extends AbstractExecutableMemberWriter
             Content linkContent = writer.getLink(
                     new LinkInfoImpl(configuration, LinkInfoImpl.Kind.RETURN_TYPE, type));
             htmltree.add(linkContent);
-            htmltree.add(Contents.SPACE);
+            htmltree.add(Entity.NO_BREAK_SPACE);
         }
     }
 

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/ModuleWriterImpl.java

@@ -25,9 +25,6 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Table;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
-
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -46,6 +43,7 @@ import javax.lang.model.util.ElementFilter;
 import com.sun.source.doctree.DocTree;
 import jdk.javadoc.doclet.DocletEnvironment.ModuleMode;
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -53,6 +51,8 @@ import jdk.javadoc.internal.doclets.formats.html.markup.Navigation;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation.PageMode;
 import jdk.javadoc.internal.doclets.formats.html.markup.RawHtml;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
+import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.ModuleSummaryWriter;
 import jdk.javadoc.internal.doclets.toolkit.util.CommentHelper;
@@ -209,7 +209,7 @@ public class ModuleWriterImpl extends HtmlDocletWriter implements ModuleSummaryW
                 ? contents.openModuleLabel : contents.moduleLabel;
         Content tHeading = HtmlTree.HEADING(Headings.PAGE_TITLE_HEADING, true,
                 HtmlStyle.title, label);
-        tHeading.add(Contents.SPACE);
+        tHeading.add(Entity.NO_BREAK_SPACE);
         Content moduleHead = new RawHtml(heading);
         tHeading.add(moduleHead);
         div.add(tHeading);
@@ -534,7 +534,7 @@ public class ModuleWriterImpl extends HtmlDocletWriter implements ModuleSummaryW
      * Add the list of modules.
      *
      * @param mdleMap map of modules and modifiers
-     * @param tbody the content tree to which the list will be added
+     * @param table the table to which the list will be added
      */
     private void addModulesList(Map<ModuleElement, Content> mdleMap, Table table) {
         for (ModuleElement m : mdleMap.keySet()) {
@@ -776,7 +776,7 @@ public class ModuleWriterImpl extends HtmlDocletWriter implements ModuleSummaryW
                     addSummaryComment(t, summary);
                 }
             } else {
-                summary.add(Contents.SPACE);
+                summary.add(Entity.NO_BREAK_SPACE);
             }
             table.addRow(typeLinkContent, summary);
         }
@@ -802,9 +802,9 @@ public class ModuleWriterImpl extends HtmlDocletWriter implements ModuleSummaryW
                 description = providesTrees.get(srv);
                 desc.add((description != null && !description.isEmpty())
                         ? HtmlTree.DIV(HtmlStyle.block, description)
-                        : Contents.SPACE);
+                        : Entity.NO_BREAK_SPACE);
             } else {
-                desc.add(Contents.SPACE);
+                desc.add(Entity.NO_BREAK_SPACE);
                 }
             // Only display the implementation details in the "all" mode.
             if (moduleMode == ModuleMode.ALL && !implSet.isEmpty()) {
@@ -812,7 +812,7 @@ public class ModuleWriterImpl extends HtmlDocletWriter implements ModuleSummaryW
                 desc.add("(");
                 HtmlTree implSpan = HtmlTree.SPAN(HtmlStyle.implementationLabel, contents.implementation);
                 desc.add(implSpan);
-                desc.add(Contents.SPACE);
+                desc.add(Entity.NO_BREAK_SPACE);
                 String sep = "";
                 for (TypeElement impl : implSet) {
                     desc.add(sep);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/NestedClassWriterImpl.java

@@ -32,6 +32,7 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.TypeElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
@@ -154,7 +155,7 @@ public class NestedClassWriterImpl extends AbstractMemberWriter
                     : resources.getText("doclet.Nested_Classes_Interfaces_Inherited_From_Class"));
         }
         Content labelHeading = HtmlTree.HEADING(Headings.TypeDeclaration.SUMMARY_HEADING, label);
-        labelHeading.add(Contents.SPACE);
+        labelHeading.add(Entity.NO_BREAK_SPACE);
         labelHeading.add(classLink);
         inheritedTree.add(labelHeading);
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/PackageUseWriter.java

@@ -25,21 +25,24 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import java.util.Set;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
+import java.util.SortedMap;
-
+import java.util.TreeMap;
-import java.util.*;
+import java.util.TreeSet;
 
 import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation.PageMode;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
+import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.util.ClassUseMapper;
 import jdk.javadoc.internal.doclets.toolkit.util.DocFileIOException;
@@ -180,7 +183,7 @@ public class PackageUseWriter extends SubWriterHolderWriter {
             if (pkg != null && !pkg.isUnnamed()) {
                 addSummaryComment(pkg, summary);
             } else {
-                summary.add(Contents.SPACE);
+                summary.add(Entity.NO_BREAK_SPACE);
             }
             table.addRow(packageLink, summary);
         }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/PackageWriterImpl.java

@@ -25,10 +25,8 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import java.util.List;
-import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
+import java.util.SortedSet;
-
-import java.util.*;
 
 import javax.lang.model.element.ModuleElement;
 import javax.lang.model.element.PackageElement;
@@ -36,12 +34,15 @@ import javax.lang.model.element.TypeElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation;
 import jdk.javadoc.internal.doclets.formats.html.markup.Navigation.PageMode;
 import jdk.javadoc.internal.doclets.formats.html.markup.StringContent;
+import jdk.javadoc.internal.doclets.formats.html.markup.Table;
+import jdk.javadoc.internal.doclets.formats.html.markup.TableHeader;
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.PackageSummaryWriter;
 import jdk.javadoc.internal.doclets.toolkit.util.CommentHelper;
@@ -120,7 +121,7 @@ public class PackageWriterImpl extends HtmlDocletWriter
             ModuleElement mdle = configuration.docEnv.getElementUtils().getModuleOf(packageElement);
             Content classModuleLabel = HtmlTree.SPAN(HtmlStyle.moduleLabelInPackage, contents.moduleLabel);
             Content moduleNameDiv = HtmlTree.DIV(HtmlStyle.subTitle, classModuleLabel);
-            moduleNameDiv.add(Contents.SPACE);
+            moduleNameDiv.add(Entity.NO_BREAK_SPACE);
             moduleNameDiv.add(getModuleLink(mdle,
                     new StringContent(mdle.getQualifiedName().toString())));
             div.add(moduleNameDiv);
@@ -130,7 +131,7 @@ public class PackageWriterImpl extends HtmlDocletWriter
         div.add(annotationContent);
         Content tHeading = HtmlTree.HEADING(Headings.PAGE_TITLE_HEADING, true,
                 HtmlStyle.title, contents.packageLabel);
-        tHeading.add(Contents.SPACE);
+        tHeading.add(Entity.NO_BREAK_SPACE);
         Content packageHead = new StringContent(heading);
         tHeading.add(packageHead);
         div.add(tHeading);

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/PropertyWriterImpl.java

@@ -25,12 +25,12 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 
 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.HtmlStyle;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTag;
 import jdk.javadoc.internal.doclets.formats.html.markup.HtmlTree;
@@ -41,7 +41,6 @@ import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.MemberSummaryWriter;
 import jdk.javadoc.internal.doclets.toolkit.PropertyWriter;
 
-
 /**
  * Writes property documentation in HTML format.
  *
@@ -161,7 +160,7 @@ public class PropertyWriterImpl extends AbstractMemberWriter
                         utils.isClass(holder)
                                 ? contents.descfrmClassLabel
                                 : contents.descfrmInterfaceLabel);
-                descfrmLabel.add(Contents.SPACE);
+                descfrmLabel.add(Entity.NO_BREAK_SPACE);
                 descfrmLabel.add(codeLink);
                 propertyDocTree.add(HtmlTree.DIV(HtmlStyle.block, descfrmLabel));
                 writer.addInlineComment(property, propertyDocTree);
@@ -263,7 +262,7 @@ public class PropertyWriterImpl extends AbstractMemberWriter
         }
         Content labelHeading = HtmlTree.HEADING(Headings.TypeDeclaration.INHERITED_SUMMARY_HEADING,
                 label);
-        labelHeading.add(Contents.SPACE);
+        labelHeading.add(Entity.NO_BREAK_SPACE);
         labelHeading.add(classLink);
         inheritedTree.add(labelHeading);
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/SerializedFormWriterImpl.java

@@ -25,10 +25,11 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import java.util.*;
+import java.util.Set;
 
 import javax.lang.model.element.TypeElement;
 
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -121,7 +122,7 @@ public class SerializedFormWriterImpl extends SubWriterHolderWriter
     public Content getPackageHeader(String packageName) {
         Content heading = HtmlTree.HEADING(Headings.SerializedForm.PACKAGE_HEADING, true,
                 contents.packageLabel);
-        heading.add(Contents.SPACE);
+        heading.add(Entity.NO_BREAK_SPACE);
         heading.add(packageName);
         return heading;
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/SingleIndexWriter.java

@@ -25,8 +25,10 @@
 
 package jdk.javadoc.internal.doclets.formats.html;
 
-import java.util.*;
+import java.util.Set;
+import java.util.TreeSet;
 
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -140,13 +142,13 @@ public class SingleIndexWriter extends AbstractIndexWriter {
             contentTree.add(
                     links.createLink(getNameForIndex(unicode),
                             new StringContent(unicode)));
-            contentTree.add(Contents.SPACE);
+            contentTree.add(Entity.NO_BREAK_SPACE);
         }
         contentTree.add(new HtmlTree(HtmlTag.BR));
         contentTree.add(links.createLink(DocPaths.ALLCLASSES_INDEX,
                 contents.allClassesLabel));
         if (!configuration.packages.isEmpty()) {
-            contentTree.add(Contents.SPACE);
+            contentTree.add(Entity.NO_BREAK_SPACE);
             contentTree.add(links.createLink(DocPaths.ALLPACKAGES_INDEX,
                     contents.allPackagesLabel));
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/SplitIndexWriter.java

@@ -32,6 +32,7 @@ import java.util.ListIterator;
 import java.util.Set;
 import java.util.TreeSet;
 
+import jdk.javadoc.internal.doclets.formats.html.markup.Entity;
 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;
@@ -163,13 +164,13 @@ public class SplitIndexWriter extends AbstractIndexWriter {
             int j = i + 1;
             contentTree.add(links.createLink(DocPaths.indexN(j),
                     new StringContent(indexElements.get(i).toString())));
-            contentTree.add(Contents.SPACE);
+            contentTree.add(Entity.NO_BREAK_SPACE);
         }
         contentTree.add(new HtmlTree(HtmlTag.BR));
         contentTree.add(links.createLink(pathToRoot.resolve(DocPaths.ALLCLASSES_INDEX),
                 contents.allClassesLabel));
         if (!configuration.packages.isEmpty()) {
-            contentTree.add(Contents.SPACE);
+            contentTree.add(Entity.NO_BREAK_SPACE);
             contentTree.add(links.createLink(pathToRoot.resolve(DocPaths.ALLPACKAGES_INDEX),
                     contents.allPackagesLabel));
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Entity.java

@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.javadoc.internal.doclets.formats.html.markup;
+
+import jdk.javadoc.internal.doclets.toolkit.Content;
+
+import java.io.IOException;
+import java.io.Writer;
+
+/**
+ * A representation of HTML entities.
+ */
+public class Entity extends Content {
+    public static final Entity LESS_THAN = new Entity("<");
+    public static final Entity GREATER_THAN = new Entity(">");
+    public static final Entity AMPERSAND = new Entity("&");
+    public static final Entity NO_BREAK_SPACE = new Entity(" ");
+    public static final Entity ZERO_WIDTH_SPACE = new Entity("​") {
+        @Override
+        public int charCount() {
+            return 0;
+        }
+    };
+
+    public final String text;
+
+    private Entity(String text) {
+        this.text = text;
+    }
+
+    @Override
+    public void add(Content content) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void add(CharSequence stringContent) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean write(Writer writer, boolean atNewline) throws IOException {
+        writer.write(text);
+        return false;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return false;
+    }
+
+    @Override
+    public int charCount() {
+        return 1;
+    }
+
+
+    /**
+     * Escapes the special HTML characters in a given string using the appropriate
+     * entities.
+     *
+     * @param s the string to escape
+     * @return the string with all of the HTML characters escaped
+     */
+    static String escapeHtmlChars(CharSequence s) {
+        for (int i = 0; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            switch (ch) {
+                // only start building a new string if we need to
+                case '<': case '>': case '&':
+                    StringBuilder sb = new StringBuilder(s.subSequence(0, i));
+                    escapeHtmlChars(s, i, sb);
+                    return sb.toString();
+            }
+        }
+        return s.toString();
+    }
+
+    /**
+     * Escapes the special HTML characters in a given string using the appropriate
+     * entities, appending the results into a string builder.
+     *
+     * @param s the string
+     * @param sb the string builder
+     */
+    static void escapeHtmlChars(CharSequence s, StringBuilder sb) {
+        escapeHtmlChars(s, 0, sb);
+    }
+
+    private static void escapeHtmlChars(CharSequence s, int start, StringBuilder sb) {
+        for (int i = start ; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            switch (ch) {
+                case '<': sb.append(Entity.LESS_THAN.text);     break;
+                case '>': sb.append(Entity.GREATER_THAN.text);  break;
+                case '&': sb.append(Entity.AMPERSAND.text);     break;
+                default:  sb.append(ch);                        break;
+            }
+        }
+    }
+
+}

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/FixedStringContent.java

@@ -47,9 +47,7 @@ public class FixedStringContent extends Content {
      * @param content content for the object
      */
     public FixedStringContent(CharSequence content) {
-        string = needEscape(content)
+        string = Entity.escapeHtmlChars(content);
-                ? escape(content)
-                : content.toString();
     }
 
     /**
@@ -105,29 +103,4 @@ public class FixedStringContent extends Content {
         return string.endsWith(DocletConstants.NL);
     }
 
-    private boolean needEscape(CharSequence cs) {
-        for (int i = 0; i < cs.length(); i++) {
-            switch (cs.charAt(i)) {
-                case '<':
-                case '>':
-                case '&':
-                    return true;
-            }
-        }
-        return false;
-    }
-    private String escape(CharSequence s) {
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < s.length(); i++) {
-            char ch = s.charAt(i);
-            switch (ch) {
-                case '<': sb.append("&lt;");  break;
-                case '>': sb.append("&gt;");  break;
-                case '&': sb.append("&amp;"); break;
-                default:  sb.append(ch);      break;
-            }
-        }
-        return sb.toString();
-    }
-
 }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/HtmlTree.java

@@ -100,7 +100,7 @@ public class HtmlTree extends Content {
     public HtmlTree put(HtmlAttr attrName, String attrValue) {
         if (attrs.isEmpty())
             attrs = new LinkedHashMap<>(3);
-        attrs.put(nullCheck(attrName), escapeHtmlChars(attrValue));
+        attrs.put(nullCheck(attrName), Entity.escapeHtmlChars(attrValue));
         return this;
     }
 
@@ -188,35 +188,6 @@ public class HtmlTree extends Content {
         return n;
     }
 
-    /**
-     * Given a string, escape all special HTML characters and
-     * return the result.
-     *
-     * @param s The string to check.
-     * @return the original string with all of the HTML characters escaped.
-     */
-    private static String escapeHtmlChars(String s) {
-        for (int i = 0; i < s.length(); i++) {
-            char ch = s.charAt(i);
-            switch (ch) {
-                // only start building a new string if we need to
-                case '<': case '>': case '&':
-                    StringBuilder sb = new StringBuilder(s.substring(0, i));
-                    for ( ; i < s.length(); i++) {
-                        ch = s.charAt(i);
-                        switch (ch) {
-                            case '<': sb.append("&lt;");  break;
-                            case '>': sb.append("&gt;");  break;
-                            case '&': sb.append("&amp;"); break;
-                            default:  sb.append(ch);      break;
-                        }
-                    }
-                    return sb.toString();
-            }
-        }
-        return s;
-    }
-
     /*
      * The sets of ASCII URI characters to be left unencoded.
      * See "Uniform Resource Identifier (URI): Generic Syntax"

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Navigation.java

@@ -429,7 +429,7 @@ public class Navigation {
                 }
                 if (!listContents.isEmpty()) {
                     Content li = HtmlTree.LI(contents.summaryLabel);
-                    li.add(Contents.SPACE);
+                    li.add(Entity.NO_BREAK_SPACE);
                     tree.add(li);
                     addListToNav(listContents, tree);
                 }
@@ -461,7 +461,7 @@ public class Navigation {
                 }
                 if (!listContents.isEmpty()) {
                     Content li = HtmlTree.LI(contents.moduleSubNavLabel);
-                    li.add(Contents.SPACE);
+                    li.add(Entity.NO_BREAK_SPACE);
                     tree.add(li);
                     addListToNav(listContents, tree);
                 }
@@ -665,7 +665,7 @@ public class Navigation {
                 }
                 if (!listContents.isEmpty()) {
                     Content li = HtmlTree.LI(contents.detailLabel);
-                    li.add(Contents.SPACE);
+                    li.add(Entity.NO_BREAK_SPACE);
                     tree.add(li);
                     addListToNav(listContents, tree);
                 }
@@ -801,9 +801,9 @@ public class Navigation {
         int count = 0;
         for (Content liContent : listContents) {
             if (count < listContents.size() - 1) {
-                liContent.add(Contents.SPACE);
+                liContent.add(Entity.NO_BREAK_SPACE);
                 liContent.add("|");
-                liContent.add(Contents.SPACE);
+                liContent.add(Entity.NO_BREAK_SPACE);
             }
             tree.add(liContent);
             count++;
@@ -1005,7 +1005,7 @@ public class Navigation {
                 fixedNavDiv.add(queue.poll());
                 fixedNavDiv.add(Position.TOP.endOfNav());
                 tree.add(fixedNavDiv);
-                HtmlTree paddingDiv = HtmlTree.DIV(HtmlStyle.navPadding, Contents.SPACE);
+                HtmlTree paddingDiv = HtmlTree.DIV(HtmlStyle.navPadding, Entity.NO_BREAK_SPACE);
                 tree.add(paddingDiv);
                 addFixedNavScript(tree);
             } else {

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/RawHtml.java

@@ -45,10 +45,6 @@ public class RawHtml extends Content {
 
     private final String rawHtmlContent;
 
-    public static final Content nbsp = new RawHtml(" ");
-
-    public static final Content zws = new RawHtml("​");
-
     /**
      * Constructor to construct a RawHtml object.
      *

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/StringContent.java

@@ -59,7 +59,7 @@ public class StringContent extends Content {
      */
     public StringContent(CharSequence initialContent) {
         stringContent = new StringBuilder();
-        appendChars(initialContent);
+        Entity.escapeHtmlChars(initialContent, stringContent);
     }
 
     /**
@@ -81,7 +81,7 @@ public class StringContent extends Content {
      */
     @Override
     public void add(CharSequence strContent) {
-        appendChars(strContent);
+        Entity.escapeHtmlChars(strContent, stringContent);
     }
 
     /**
@@ -114,16 +114,4 @@ public class StringContent extends Content {
         out.write(s);
         return s.endsWith(DocletConstants.NL);
     }
-
-    private void appendChars(CharSequence s) {
-        for (int i = 0; i < s.length(); i++) {
-            char ch = s.charAt(i);
-            switch (ch) {
-                case '<': stringContent.append("&lt;");  break;
-                case '>': stringContent.append("&gt;");  break;
-                case '&': stringContent.append("&amp;"); break;
-                default:  stringContent.append(ch);      break;
-            }
-        }
-    }
 }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Table.java

@@ -531,6 +531,6 @@ public class Table {
     private HtmlTree getCaption(Content title) {
         return new HtmlTree(HtmlTag.CAPTION,
                 HtmlTree.SPAN(title),
-                HtmlTree.SPAN(tabEnd, Contents.SPACE));
+                HtmlTree.SPAN(tabEnd, Entity.NO_BREAK_SPACE));
     }
 }