[FIXED] Maven is not working in Java 8 when Javadoc tags are incomplete

Issue

Since I use Maven I have been able to build and install in my local repository projects that have incomplete Javadoc tags (for example, a missing parameter).

However, since I migrated to Java 8 (1.8.0-ea-b90) Maven is absolutely strict about missing documentation tags and show me lots of Javadoc errors related to Javadoc problems when I try to build or install a project where the Javadoc is not "perfect". Some of the projects I am trying to compile and install in my local repository are third party projects from which I do not have control. So the workaround of just fixing all the Javadocs in all these projects does not seem to be feasable in my scenario.

This is a small part of the output I see when I execute mvn clean package install in my project:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 9.026s
[INFO] Finished at: Mon Apr 08 21:06:17 CEST 2013
[INFO] Final Memory: 27M/437M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.9:jar (attach-javadocs) on project jpc: MavenReportException: Error while creating archive:
[ERROR] Exit code: 1 - /Users/sergioc/Documents/workspaces/heal/jpc/src/main/java/org/jpc/engine/prolog/PrologDatabase.java:10: error: @param name not found
[ERROR] * @param terms the terms to assert
[ERROR] ^
[ERROR] /Users/sergioc/Documents/workspaces/heal/jpc/src/main/java/org/jpc/engine/prolog/PrologDatabase.java:11: warning: no description for @return
[ERROR] * @return
[ERROR] ^

The Javadoc Maven plugin is configured like this in my POM:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>2.9</version>
    <executions>
        <execution>
            <id>attach-javadocs</id>
            <goals>
                <goal>jar</goal>
            </goals>
        </execution>
    </executions>
</plugin>

As I said before, everything is working fine if I go back to Java 7. Maybe is this a bug related to Maven running in Java 8? How could I make it work (i.e., being able to build the Javadoc of the project and install its code in my local repository) with Java 8? I have tested with both Maven 3.0.3 and 3.0.5 in OSX.

UPDATE:

If I change my Javadoc plugin configuration with <failOnError>false</failOnError> (thanks Martin):

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>2.9</version>
    <executions>
        <execution>
            <id>attach-javadocs</id>
            <goals>
                <goal>jar</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Then the project is installed in my local repository. However, the Javadoc JAR is still not generated.

A fragment of the output I see in the console with this new configuration is:

[ERROR] MavenReportException: Error while creating archive: Exit code: 1 - /Users/....java:18: warning: no @param ... Command line was: /Library/Java/Home/bin/javadoc @options @packages

Refer to the generated Javadoc files in '/Users/sergioc/Documents/workspaces/heal/minitoolbox/target/apidocs' dir.

at org.apache.maven.plugin.javadoc.AbstractJavadocMojo.executeJavadocCommandLine(AbstractJavadocMojo.java:5043) at org.apache.maven.plugin.javadoc.AbstractJavadocMojo.executeReport(AbstractJavadocMojo.java:1990) at org.apache.maven.plugin.javadoc.JavadocJar.execute(JavadocJar.java:181) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59) at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196) at org.apache.maven.cli.MavenCli.main(MavenCli.java:141) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:491) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)

Any workaround about how to build the sources, install the project and generate the Javadoc JAR in one step as it was working with Java 7?

Solution

The best solution would be to fix the javadoc errors. If for some reason that is not possible (ie: auto generated source code) then you can disable this check.

DocLint is a new feature in Java 8, which is summarized as:

Provide a means to detect errors in Javadoc comments early in the development cycle and in a way that is easily linked back to the source code.

This is enabled by default, and will run a whole lot of checks before generating Javadocs. You need to turn this off for Java 8 as specified in this thread. You'll have to add this to your maven configuration:

<profiles>
  <profile>
    <id>java8-doclint-disabled</id>
    <activation>
      <jdk>[1.8,)</jdk>
    </activation>
    <properties>
      <javadoc.opts>-Xdoclint:none</javadoc.opts>
    </properties>
  </profile>
</profiles>
<build>
  <plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <version>2.9</version>
        <executions>
            <execution>
                <id>attach-javadocs</id>
                <goals>
                    <goal>jar</goal>
                </goals>
                <configuration>
                    <additionalparam>${javadoc.opts}</additionalparam>
                </configuration>
            </execution>
        </executions>
    </plugin>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-site-plugin</artifactId>
        <version>3.3</version>
        <configuration>
          <reportPlugins>
            <plugin>
              <groupId>org.apache.maven.plugins</groupId>
              <artifactId>maven-javadoc-plugin</artifactId>
              <configuration>
                <additionalparam>${javadoc.opts}</additionalparam>
              </configuration>
            </plugin>
          </reportPlugins>
        </configuration>
      </plugin>
   </plugins>
</build>

For maven-javadoc-plugin 3.0.0+: Replace

<additionalparam>-Xdoclint:none</additionalparam>

with

<doclint>none</doclint>

Answered By - Subhas
Answer Checked By - Clifford M. (JavaFixing Volunteer)