JDK8: Getting back the JDK7 look for javadoc

Question

I find it difficult to read the new look-and-feel in JDK8 javadoc compared to JDK7. Here\'s a side-by-side example.

JDK7:

Answer 1

I use a style sheet to override some of the JDK8 CSS definitions, to make it look mostly like JDK7 Javadoc.

@import "stylesheetOrig.css";

body {
   font-family: Arial, Helvetica, sans-serif;
   font-size: 12px; }

pre {
   font-family: monospace;
   font-size: 12px; }

code, tt, dt code, table tr td dt code  {
   font-family: monospace;
   font-size: 12px; }

.contentContainer .description dl dt, .contentContainer .details dl dt, .serializedFormContainer dl dt {
   font-size: 13px; }

.contentContainer .description dl dd, .contentContainer .details dl dd, .serializedFormContainer dl dd {
   margin-left: 20px;
   font-size: 12px;
   font-family: inherit; }

div.block {
   font-size: 12px;
   font-family: inherit; }

h4 {
   font-size: 15px; }

.memberSummary caption {
   padding-top: 0; }

div.summary th {
   border: 1px solid #9eadc0; }
div.summary td {
   border-left: 1px solid #9eadc0;
   border-right: 1px solid #9eadc0; }
div.summary th.colFirst,
div.summary td.colFirst {
   border-right: none; }
div.summary th.colLast,
div.summary td.colLast {
   border-left: none; }
div.summary table {
   border-bottom: 1px solid #9eadc0;
   margin-bottom: 15px; }
div.summary ul.blockList ul.blockList ul.blockList {
   margin-top: 20px; }
ul.blockList ul.blockList li.blockList,
ul.blockList ul.blockList ul.blockList li.blockList,
ul.blockList ul.blockList ul.blockListLast li.blockList {
   border: 1px solid #9eadc0; }
div.summary ul.blockList ul.blockList ul.blockList li.blockList h3,
div.details ul.blockList ul.blockList ul.blockList li.blockList h4,
div.details ul.blockList ul.blockList ul.blockListLast li.blockList h4 {
   border-bottom: 1px solid #9eadc0; }

My Ant script renames the original stylesheet.css to stylesheetOrig.css and replaces it with the new version (which imports the original version):

<condition property="isJava8">
 <equals arg1="${ant.java.version}" arg2="1.8"/>
</condition>

<target name="-fixupJava8Javadoc" if="isJava8">
 <move file="target/apidocs/stylesheet.css" tofile="target/apidocs/stylesheetOrig.css"/>
 <copy file="src/doc/javadoc8OverrideStylesheet.css" tofile="target/apidocs/stylesheet.css"/>
</target>

Answer 2

The css used in Java 7's Javadoc can be found here:

http://docs.oracle.com/javase/7/docs/api/stylesheet.css

You can then use the stylesheetfile attribute from the javadoc commandline, or ant or maven

from commandline:

%javadoc -stylesheetfile <path> ...

in ant:

<javadoc 
        ....
        stylesheetfile="/path/to/stylesheet.css"
        />      

in Maven (see Maven's stylesheet configuration page for more details ):

<reporting> (or <build>)
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        ...
        <configuration>
          <stylesheetfile>${basedir}/path/to/your/stylesheetfile.css</stylesheetfile>
          ...
        </configuration>
      </plugin>
    </plugins>
    ...
  </reporting> (or </build>) 

UPDATE

Stephen Colebourne has an article about other breaking changes to Javadoc in Java 8 here . Apparently, the doclint now enforces HTML 4 compliance and will not link if the link is broken or not 100% correct HTML 4. You can turn it off with -Xdoclint:none as an additional parameter.

<plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-javadoc-plugin</artifactId>
      <configuration>
        <additionalparam>-Xdoclint:none</additionalparam>
      </configuration>
    </plugin>
 </plugins>

Regarding the <code> tags in parameter descriptions, I did see that too. It looks like the parameter descriptions in javadoc are now always monospace so you don't need code tags anymore?

Answer 3

You could get the standard JDK 8 stylesheet.css and fix it very quickly, and then you can put that into some source folder and tell javadoc to use that with its stylesheetfile option. The problem with that is that there's no backward compatibility guarantee, the generated HTML changes quite a bit sometimes. That happened with JDK 7, and now with JDK 8. And then often you also have to consider that just because JDk 8 is out, some may will build your project with JDK 7...

Anyway, what I did was detecting if we are building under JDK 8 or later, and in that case I have applied regexp replacements on stylesheet.css, on build time. That was easy for me, as this old project uses Ant, not Maven. Just to see what the changes are, the relevant part is:

<target name="_fixJDK8JavadocCSS" depends="_rawJavadoc" if="atLeastJDK8">
  <property name="file" value="build/api/stylesheet.css" />
  <echo>Fixing JDK 8 CSS in ${file}</echo>

  <!-- Tell that it's modified: -->
  <replaceregexp
      file="${file}" flags="gs" encoding="utf-8"
      match="/\* (Javadoc style sheet) \*/" replace="/\* \1 - JDK 8 usability fix regexp substitutions applied \*/"
  />

  <!-- Remove broken link: -->
  <replaceregexp
      file="${file}" flags="gs" encoding="utf-8"
      match="@import url\('resources/fonts/dejavu.css'\);\s*" replace=""
  />

  <!-- Font family fixes: -->
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="['&quot;]DejaVu Sans['&quot;]" replace="Arial"
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="['&quot;]DejaVu Sans Mono['&quot;]" replace="'Courier New'"
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="['&quot;]DejaVu Serif['&quot;]" replace="Arial"
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="(?&lt;=[\s,:])serif\b" replace="sans-serif"
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="(?&lt;=[\s,:])Georgia,\s*" replace=""
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="['&quot;]Times New Roman['&quot;],\s*" replace=""
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="(?&lt;=[\s,:])Times,\s*" replace=""
  />
  <replaceregexp
      file="${file}" flags="gsi" encoding="utf-8"
      match="(?&lt;=[\s,:])Arial\s*,\s*Arial\b" replace="Arial"
  />

  <!-- "Parameters:", "Returns:", "Throws:", "Since:", "See also:" etc. fixes: -->
  <property name="ddSelectorStart" value="(?:\.contentContainer\s+\.(?:details|description)|\.serializedFormContainer)\s+dl\s+dd\b.*?\{[^\}]*\b" />
  <property name="ddPropertyEnd" value="\b.+?;" />
  <!-- - Put back description (dd) indentation: -->
  <replaceregexp
      file="${file}" flags="gs" encoding="utf-8"
      match="(${ddSelectorStart})margin${ddPropertyEnd}" replace="\1margin: 5px 0 10px 20px;"
  />
  <!-- - No monospace font for the description (dd) part: -->
  <replaceregexp
      file="${file}" flags="gs" encoding="utf-8"
      match="(${ddSelectorStart})font-family${ddPropertyEnd}" replace="\1"
  />
</target>

So the point is the regular expression above, that anyone can apply with ant, sed, Notepad++, etc (for non-Ant, don't forget to resolve the &...; and ${...} parts).

The reason I have used regexp is that I hope that it will be able to survive some changes in the HTML and thus in the standard CSS... but maybe I should just use the resulting CSS, I don't know. Or I should opt for using some 3rd party doclet, where thus I can control the used version.