Using Eclipse compiler instead of javac results in javadoc crash

Question

Summary:

I've run into an interesting problem, and I'm not quite sure how to sleuth it:

• Our project has been building fine for months
• I changed the maven-compiler-plugin to use the eclipse compiler instead of javac
• Now when I run mvn site, maven-javadoc-plugin fails
• According to the stack trace, it appears the Javadoc tool is crashing on a class file created by the Eclipse compiler

Is there any way to fix this? If not, is there at least any way to debug it further?

Full details:

I'm using Java 1.6.0_27 and Maven 3.0.2.

I've been using the javac compiler to build our codebase, but I'm interested in trying the Eclipse compiler, since it produces much better warnings (and is more configurable in other ways).

So I changed the definition of the maven-compiler-plugin in the pom.xml to:

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    <configuration>
        <compilerId>eclipse</compilerId>
        <source>1.6</source>
        <target>1.6</target>
        <compilerArgument>-warn:+boxing,enumSwitch,javadoc,hashCode</compilerArgument>
        <showWarnings>true</showWarnings>
        <showDeprecation>true</showDeprecation>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>org.codehaus.plexus</groupId>
            <artifactId>plexus-compiler-eclipse</artifactId>
            <version>1.8.2</version>
        </dependency>
    </dependencies>
</plugin>

In my <reporting> section, I have:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>2.8</version>
</plugin>

So far, so good. I did a mvn clean install and everything builds fine, all the tests pass, and everything looks great.

But when I try to run mvn site, when it gets to the Javadoc report, it fails with what appears to be a Javadoc crash:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.0:site (default-site) on project framework: Error during page generation: Error rendering Maven report:
[ERROR] Exit code: 1 - java.lang.StringIndexOutOfBoundsException: String index out of range: -15
[ERROR] at java.lang.String.substring(String.java:1937)
[ERROR] at java.lang.String.substring(String.java:1904)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.simpleBinaryName(ClassReader.java:958)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readEnclosingMethodAttr(ClassReader.java:930)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readMemberAttr(ClassReader.java:909)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readClassAttr(ClassReader.java:1053)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readClassAttrs(ClassReader.java:1067)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readClass(ClassReader.java:1560)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.readClassFile(ClassReader.java:1658)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.fillIn(ClassReader.java:1845)
[ERROR] at com.sun.tools.javac.jvm.ClassReader.complete(ClassReader.java:1777)
[ERROR] at com.sun.tools.javac.code.Symbol.complete(Symbol.java:386)
[ERROR] at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:763)
[ERROR] at com.sun.tools.javac.code.Symbol$ClassSymbol.flags(Symbol.java:695)
[ERROR] at com.sun.tools.javadoc.ClassDocImpl.getFlags(ClassDocImpl.java:105)
[ERROR] at com.sun.tools.javadoc.ClassDocImpl.isAnnotationType(ClassDocImpl.java:116)
[ERROR] at com.sun.tools.javadoc.DocEnv.isAnnotationType(DocEnv.java:574)
[ERROR] at com.sun.tools.javadoc.DocEnv.getClassDoc(DocEnv.java:546)
[ERROR] at com.sun.tools.javadoc.PackageDocImpl.getClasses(PackageDocImpl.java:154)
[ERROR] at com.sun.tools.javadoc.PackageDocImpl.addAllClassesTo(PackageDocImpl.java:170)
[ERROR] at com.sun.tools.javadoc.RootDocImpl.classes(RootDocImpl.java:178)
[ERROR] at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.startGeneration(AbstractDoclet.java:96)
[ERROR] at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.start(AbstractDoclet.java:64)
[ERROR] at com.sun.tools.doclets.formats.html.HtmlDoclet.start(HtmlDoclet.java:42)
[ERROR] at com.sun.tools.doclets.standard.Standard.start(Standard.java:23)
[ERROR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[ERROR] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[ERROR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[ERROR] at java.lang.reflect.Method.invoke(Method.java:597)
[ERROR] at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:269)
[ERROR] at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:143)
[ERROR] at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:340)
[ERROR] at com.sun.tools.javadoc.Start.begin(Start.java:128)
[ERROR] at com.sun.tools.javadoc.Main.execute(Main.java:41)
[ERROR] at com.sun.tools.javadoc.Main.main(Main.java:31)
[ERROR] 
[ERROR] Command line was: "C:\Program Files (x86)\Java\jdk1.6.0_27\jre\..\bin\javadoc.exe" @options @packages
[ERROR] 
[ERROR] Refer to the generated Javadoc files in 'C:\Projects\SMF\framework\target\site\apidocs' dir.
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[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

My Question:

OK, so what changed? All the Javadoc and the Maven site were building just fine when I was using javac, but as soon as I switched to the Eclipse compiler, Javadoc crashes.

Worse, it doesn't even tell me what class caused it to crash, so I don't even know where to begin debugging this.

Obviously, for the time being this means that I'm not going to use the Eclipse compiler, and I'm going to stick with javac instead. But I'm curious as to why this is happening, and what I could possibly do to fix or work around it.

Answer 1

I finally got some time to look into this again. The maven-javadoc-plugin helpfully leaves behind a javadoc.bat script under target/site/apidocs when the javadoc.exe process fails, and I was able to find the offending package by pruning the list in the packages file that gets passed into javadoc.exe.

Interestingly, the problematic code turned out to be the Java source generated by the Google Protocol Buffers compiler. This was fortunate, since it's acceptable to simply exclude the protobuf-generated source from the Javadoc entirely.

I added the following definition, under both my <build> and <reporting> sections of the POM, and this resolved my issue:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>2.6.1</version>
    <configuration>
        <excludePackageNames>com.mycompany.myproject.proto</excludePackageNames>
    </configuration>
</plugin>

Answer 2

Workaround for this would be to create a separate profile for the site goal. So that you could define different compilers for different goals.