Maven javadoc plugin issue : Comparison method violates its general contract

Question

When deploying an artifact I get this strange error from the Maven javadoc plugin

C:\Users\oomsa\dev\eclipse\chemspot\src\main\java\org\u_compare\shared\label\penn\function\text\TTL_Type.java:60: warning - @generated is an unknown tag.
C:\Users\oomsa\dev\eclipse\chemspot\src\main\java\org\u_compare\shared\label\penn\function\text\TTL_Type.java:24: warning - @generated is an unknown tag.
javadoc: error - Exception processing overview.
javadoc: error - java.lang.IllegalArgumentException: Comparison method violates its general contract!

Command line was: "C:\Program Files\Java\jdk1.7.0_65\jre\..\bin\javadoc.exe" @options @argfile

Refer to the generated Javadoc files in 'C:\Users\oomsa\dev\eclipse\chemspot\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)
        ... 21 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

It only does that with a specific project, not with the others. What could have gone wrong?

Answer 1

Looks like you are generating javadoc from the base sources, and not the ones that have some sort of generated code stubs in them.

Just before the failure, you have errors that the @generated tags are unknown. I'll bet that you are missing some critical bits of information (like some, if not all of the source code) to compile your javadoc because the source code is missing.

Have you opened the files in question and looked at them? That's a good place to start.