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

327
votes

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?

18
javamavenmigrationjava-8javadoc
Hi @75inchpianist, I have updated the question, in fact they are errors (although surprisingly enough the last line of the error refers to a warning, as you can see in the generated output). The project is not installed in my local repository, so it is not considered as a simple warning :( – Sergio
For GoogleJuice: I got the error "error: bad use of '>'" because I had a big arrow in JavaDoc comment – Drew Stephens
Maybe it will be useful for someone: You can easily find all this incomplete tags in IntelliJ by running inspection Ctrl+Alt+Shift+i "Declaration has JavaDoc problems" – Sergey Ponomarev
This is not maven, it is the javadoc program which got a lot stricter in Java 8. – Thorbjørn Ravn Andersen

18 Answers

402
votes

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>
98
votes

The easiest approach to get things working with both java 8 and java 7 is to use a profile in the build:

<profiles>
  <profile>
    <id>doclint-java8-disable</id>
    <activation>
      <jdk>[1.8,)</jdk>
    </activation>

    <build>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-javadoc-plugin</artifactId>
          <configuration>
            <additionalparam>-Xdoclint:none</additionalparam>
          </configuration>
        </plugin>
      </plugins>
    </build>
  </profile>
</profiles>
65
votes

Here is the most concise way I am aware of to ignore doclint warnings regardless of java version used. There is no need to duplicate plugin configuration in multiple profiles with slight modifications.

<profiles>
  <profile>
    <id>doclint-java8-disable</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>2.9.1</version>
      <executions>
        <execution>
          <id>attach-javadocs</id> <!-- The actual id should be apparent from maven output -->
          <configuration>
            <additionalparam>${javadoc.opts}</additionalparam>
          </configuration>
        </execution>
      </executions>
    </plugin>
    ...
  </plugins>
</build>

Tested on oracle/open jdk 6, 7, 8 and 11.

42
votes

The shortest solution that will work with any Java version:

<profiles>
    <profile>
        <id>disable-java8-doclint</id>
        <activation>
            <jdk>[1.8,)</jdk>
        </activation>
        <properties>
            <additionalparam>-Xdoclint:none</additionalparam>
        </properties>
    </profile>
</profiles>

Just add that to your POM and you're good to go.

This is basically @ankon's answer plus @zapp's answer.

For maven-javadoc-plugin 3.0.0 users:

Replace

<additionalparam>-Xdoclint:none</additionalparam>

by

<doclint>none</doclint>

38
votes

Add into the global properties section in the pom file:

<project>
    ...
    <properties>
        <additionalparam>-Xdoclint:none</additionalparam>
    </properties>

The common solution provided here in the other answers (adding that property in the plugins section) did not work for some reason. Only by setting it globally I could build the javadoc jar successfully.

33
votes

I don't think just turning off DocLint is a good solution, at least not long term. It is good that Javadoc has become a bit more strict so the right way to fix the build problem is to fix the underlying problem. Yes, you'll ultimately need to fix those source code files.

Here are the things to look out for that you could previously get away with:

  • Malformed HTML (for example a missing end-tag, un-escaped brackets, etc)
  • Invalid {@link }s. (same goes for similar tags such as @see)
  • Invalid @author values. This used to be accepted : @author John <[email protected]> but not so anymore because of the un-escaped brackets.
  • HTML tables in Javadoc now require a summary or caption. See this question for explanation.

You'll simply have to fix your source code files and keep building your Javadoc until it can build without a failure. Cumbersome yes, but personally I like when I have brought my projects up to DocLint level because it means I can be more confident that the Javadoc I produce is actually what I intend.

There's of course the problem if you are generating Javadoc on some source code you've not produced yourself, for example because it comes from some code generator, e.g. wsimport. Strange that Oracle didn't prepare their own tools for JDK8 compliance before actually releasing JDK8. It seems it won't be fixed until Java 9. Only in this particular case I suggest to turn off DocLint as documented elsewhere on this page.

31
votes

Overriding maven-javadoc-plugin configuration only, does not fix the problem with mvn site (used e.g during the release stage). Here's what I had to do:

<profile>
  <id>doclint-java8-disable</id>
  <activation>
    <jdk>[1.8,)</jdk>
  </activation>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <configuration>
          <additionalparam>-Xdoclint:none</additionalparam>
        </configuration>
      </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>-Xdoclint:none</additionalparam>
              </configuration>
            </plugin>
          </reportPlugins>
        </configuration>
      </plugin>
    </plugins>
  </build>
</profile>
25
votes

You could try setting the failOnError property (see plugin documentation) to false:

<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>
              <failOnError>false</failOnError>
            </configuration>
        </execution>
    </executions>
</plugin>

As you can see from the docs, the default value is true.

18
votes

Since it depends on the version of your JRE which is used to run the maven command you propably dont want to disable DocLint per default in your pom.xml

Hence, from command line you can use the switch -Dadditionalparam=-Xdoclint:none.

Example: mvn clean install -Dadditionalparam=-Xdoclint:none

10
votes

The configuration property name has been changed in the latest version of maven-javadoc-plugin which is 3.0.0.

Hence the <additionalparam> will not work. So we have to modify it as below.

   <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-javadoc-plugin</artifactId>
      <version>3.0.0</version>
      <configuration>
         <doclint>none</doclint>
      </configuration>
  </plugin>
4
votes

I would like to add some insight into other answers

In my case

-Xdoclint:none

Didn't work.

Let start with that, in my project, I didn't really need javadoc at all. Only some necessary plugins had got a build time dependency on it.

So, the most simple way solve my problem was: 

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <configuration>
        <skip>true</skip>
    </configuration>
</plugin>
4
votes

As of maven-javadoc-plugin 3.0.0 you should have been using additionalJOption to set an additional Javadoc option, so if you would like Javadoc to disable doclint, you should add the following property. 

<properties>
    ...
    <additionalJOption>-Xdoclint:none</additionalJOption>
    ...
<properties>

You should also mention the version of maven-javadoc-plugin as 3.0.0 or higher. 

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>3.0.0</version>    
</plugin>
3
votes

So, save yourself some hours that I didn't and try this if it seems not to work:

 <additionalJOption>-Xdoclint:none</additionalJOption>

The tag is changed for newer versions.

3
votes

Added below

JAVA_TOOL_OPTIONS=-DadditionalJOption=-Xdoclint:none

Into Jenkins job :

Configuration > Build Environment > Inject environment variables to the build process > Properties Content

Solved my problem of code building through Jenkins Maven :-)

2
votes

I'm not sure if this is going to help, but even i faced the exact same problem very recently with oozie-4.2.0 version. After reading through the above answers i have just added the maven option through command line and it worked for me. So, just sharing here.

I'm using java 1.8.0_77, haven't tried with java 1.7

bin/mkdistro.sh -DskipTests -Dmaven.javadoc.opts='-Xdoclint:-html'

1
votes

To ignore missing @param and @return tags, it's enough to disable the missing doclint group. This way, the javadoc will still be checked for higher level and syntax issues:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <version>3.0.0</version>
        <configuration>
            <doclint>all,-missing</doclint>
        </configuration>
    </plugin>

Note that this is for plugin version 3.0 or newer.

0
votes

I'm a bit late to the party, but I was forced to search for workaround too, ended up here, and then found it.

Here's what works for me:-

export JAVA_TOOL_OPTIONS=-DadditionalJOption=-Xdoclint:none

And then start your Maven build, any Linux distribution build etc. Nice thing about it that it doesn't require Maven config files modification - I couldn't do that as my objective was to rebuild a bunch of Centos rpm packages, so had to go really deep.

0
votes

In my case I was using a parent pom (not sure it was the real cause since I was running against the clock), maven 2.x and java 1.6 were used, for some reason above solutions didn't work, so I added the following profile and managed it to make it run:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany</groupId>
    <artifactId>myapp</artifactId>
    <packaging>war</packaging>
    <name>myapp</name>
    <version>0.0.1-SNAPSHOT</version>
    <description>My App</description>
    <parent>
        <groupId>com.mycompany</groupId>
        <artifactId>parent-artifact</artifactId>
        <version>0.0.1</version>
    </parent>

    <profiles>
        <profile>
            <id>doclint-java6-disable</id>
            <activation>
                <jdk>[1.6,)</jdk>
            </activation>
            <properties>
                <additionalparam>--allow-script-in-comments</additionalparam>
            </properties>
        </profile>
    </profiles>
</project>