How do I get Hudson to generate a Findbugs report without failing due to an exception?

Question

Update

As of Hudson Findbugs plug-in version 4.3 this is no longer an issue

End Update

As an example of my problem, I'm trying to build the following project http://www.sonatype.com/books/mvnex-book/reference/multimodule.html

I added the following to simple-parent/pom.xml

<reporting>
  <plugins>
    <plugin>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>findbugs-maven-plugin</artifactId>
      <version>2.3</version>
      <configuration>
         <findbugsXmlOutput>true</findbugsXmlOutput>
         <findbugsXmlWithMessages>true</findbugsXmlWithMessages>
         <xmlOutput>true</xmlOutput>
      </configuration>
    </plugin>
  </plugins>
</reporting>

And the following to simple-weather/pom.xml and simple-webapp/pom.xml

<reporting>
  <plugins>
    <plugin>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>findbugs-maven-plugin</artifactId>
    </plugin>
  </plugins>
</reporting>

I inserted the following horrible equals method into one of the classes to have FindBugs generate some issues (as there is no error on 0 bugs):

public boolean equals(Object o) { return true; }

I'm using Hudson with a maven2 style project. The job is aimed at the simple-parent pom with the goals

clean site

I get the following exception:

[INFO] Generating "FindBugs Report" report.
[java] Warnings generated: 2
[INFO] ------------------------------------------------------------------------
[ERROR] FATAL ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Cannot inherit from final class
[INFO] ------------------------------------------------------------------------
[INFO] Trace
java.lang.VerifyError: Cannot inherit from final class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at hudson.remoting.RemoteClassLoader$ClassLoaderProxy.fetch2(RemoteClassLoader.java:370)
at sun.reflect.GeneratedMethodAccessor594.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:274)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:417)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
at java.util.concurrent.FutureTask.run(FutureTask.java:123)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:651)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:676)
at java.lang.Thread.run(Thread.java:595)

Version info:

• Maven 2.2.1
• Java 1.5.0_22
• Hudson 1.341 (also found on 1.339) running inside JBoss 4.0.5.GA (same error on 4.2.2.GA and 5.1.0.GA)
• Maven FindBugs plugin 2.3
• Hudson FindBugs plugin 4.1

Any ideas on how to fix this?

Answer 1

According to the FindBugs FAQ, this problem occurs when the wrong version of Apache BCEL is being used (see Q2: When I click the "Find Bugs!" button, I get a NoSuchMethodError or VerifyError). In your case, I suspect that the maven-findbugs-plugin is getting the BCEL library from JBoss because of some obscure classloading issue. There are some very similar bugs in Hudson's Jira, e.g. HUDSON-5134 (the hudson findbugs plugin is also affected).

My understanding is that this problem has been introduced recently (in v1.338) and, even if there is a workaround, it is an Hudson bug (it is a regression, it's not a problem with JBoss).

Now, you have IMO two solutions:

• Use a version of Hudson anterior to v1.338 (the regression was reported for this version) but using an old version and sticking with it is certainly not really a viable solution.
• Remove or replace the bcel.jar of JBoss (in server/SERVERNAME/lib) with the version used by the maven-findbugs-plugin (see dependencies). I'm not able to say how this will affect JBoss exactly (If you remove it, it seems that you will loose the ability to run JBoss in debug-mode but I can't say if everything will work fine if you replace it).

Whatever you'll do, please create a new Jira issue (http://issues.hudson-ci.org/) as this is a regression in Hudson. They have marked HUDSON-5134 as "Won't fix" because there is a workaround but I don't think that messing with JBoss libraries is a good solution (I'm repeating myself but this is a Hudson bug). So, insisting and letting Hudson developers know that other users are affected by this problem will help all the entire community (at least, I hope so).

Answer 2

The other answers provided are better, but one alternative to add: use Ant or batch file to create a separate build step that doesn't care that the FindBugs step failed. The Hudson plug-in can still be used to display the results.

Answer 3

As Pascal points out, there is a similar bug filed - HUDSON-5134 - and that bug indicates the behavior started with Hudson release 1.338. Since Hudson releases once a week, it can be difficult to pin down which version introduced a bug. I notice there was a classloader related change released with Hudson version 1.337 (HUDSON-5048), and I suspect that is causing the problem here, but I don't have direct evidence of that.

But that likely means you need to roll back to 1.337 or earlier to avoid this problem.