Build fails (Task :archunit:javadoc)

[kamer]

Hello! I have cloned the project to contribute and tried to build following the Contributing Guide. But it fails as below. It's the first time I'm using Gradle so I couldn't do anything aside from Googling it and changing Java versions.

• Linux 5.4.6-2-MANJARO
  I tried with:
• openjdk 13.0.1 2019-10-15 (It outputs unsupported class file error)
• openjdk 10.0.2 2018-07-17
• oracle java 9.0.4

javadoc: error - An exception occurred while building a component: TagInfo
	(java.lang.NullPointerException)
Please file a bug against the javadoc tool via the Java bug reporting page
(http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com)
for duplicates. Include error messages and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
	at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getEnclosingTypeElement(Utils.java:2574)
	at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.CommentHelper.getReferencedClass(CommentHelper.java:371)
    ...
    ... [I removed this part intentionally.]
    ...
 
1 error

> Task :archunit:javadoc FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':archunit:javadoc'.
> Javadoc generation failed. Generated Javadoc options file (useful for troubleshooting): '/home/kamer/downloads/ArchUnit/archunit/build/tmp/javadoc/javadoc.options'

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 10s
34 actionable tasks: 29 executed, 5 up-to-date

Running it with --stacktrace gives some additional info:

> Task :archunit-example:example-plain:compileJava FAILED
/home/kamer/downloads/ArchUnit/archunit-example/example-plain/src/main/java/com/tngtech/archunit/example/plantuml/importer/ProductImport.java:8: error: error while writing ProductImport: /home/kamer/downloads/ArchUnit/archunit-example/example-plain/build/classes/java/main/com/tngtech/archunit/example/plantuml/importer/ProductImport.class
public class ProductImport {
       ^
1 error

> Task :archunit:compileJava FAILED
/home/kamer/downloads/ArchUnit/archunit/src/main/java/com/tngtech/archunit/base/ReflectionUtils.java:23: error: error while writing ReflectionUtils: /home/kamer/downloads/ArchUnit/archunit/build/classes/java/main/com/tngtech/archunit/base/ReflectionUtils.class
public class ReflectionUtils {
       ^
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
`

[hankem]

First of all, thanks for your interest to contribute to ArchUnit! 😃

Issues

JDK 9 / 10

I can confirm the issues with Java 9 and 10, but note the following message:

Please file a bug against the javadoc tool via the Java bug reporting page

So this is indeed a JDK issue – which has been fixed in newer versions, but I guess that this fix won't be backported to JDK 9 or 10.

JDK 13

Regarding the issues with JDK 13: With openjdk-13.0.2, I'm also getting (tons of errors like)

> Task :archunit:spotbugsMain
The following errors occurred during analysis:
  Error scanning java/lang/Object for referenced classes
    java.lang.IllegalArgumentException: Unsupported class file major version 57
      At org.objectweb.asm.ClassReader.<init>(ClassReader.java:176)
      At org.objectweb.asm.ClassReader.<init>(ClassReader.java:158)
      At org.objectweb.asm.ClassReader.<init>(ClassReader.java:146)
      At edu.umd.cs.findbugs.asm.FBClassReader.<init>(FBClassReader.java:35)
      At edu.umd.cs.findbugs.classfile.engine.asm.ClassReaderAnalysisEngine.analyze(ClassReaderAnalysisEngine.java:48)
      At edu.umd.cs.findbugs.classfile.engine.asm.ClassReaderAnalysisEngine.analyze(ClassReaderAnalysisEngine.java:34)
      At edu.umd.cs.findbugs.classfile.impl.AnalysisCache.getClassAnalysis(AnalysisCache.java:262)
      At edu.umd.cs.findbugs.classfile.engine.ClassInfoAnalysisEngine.analyze(ClassInfoAnalysisEngine.java:75)
      At edu.umd.cs.findbugs.classfile.engine.ClassInfoAnalysisEngine.analyze(ClassInfoAnalysisEngine.java:38)
      At edu.umd.cs.findbugs.classfile.impl.AnalysisCache.getClassAnalysis(AnalysisCache.java:262)
      At edu.umd.cs.findbugs.FindBugs2.buildReferencedClassSet(FindBugs2.java:774)
      At edu.umd.cs.findbugs.FindBugs2.execute(FindBugs2.java:220)
      At com.github.spotbugs.internal.spotbugs.SpotBugsExecuter.runSpotbugs(SpotBugsExecuter.java:23)

I believe that we need to update spotbugs in order to support building ArchUnit with JDK ≥13 (the same was needed to support JDK 11 with #119), and that this, in turn, requires the gradle update of #192.

Workaround

So for the time being, you could either

• use (Open)JDK 11 or 12 (preferred), or
• use (Open)JDK 13 and locally skip spotbugs, e.g. by (temporarily) removing the following line in build-steps/build-steps.gradle:

 def utilsPath = { "build-steps/${it}" }
 
 apply from: utilsPath('archiving/archiving.gradle')
-apply from: utilsPath('codequality/spotbugs.gradle')
 apply from: utilsPath('release/publish.gradle')
 apply from: utilsPath('license/license.gradle')
 apply from: utilsPath('maven-integration-test/maven-integration-test.gradle')

[kamer]

@hankem Thank you for detailed answer. It works fine with JDK11.

[hankem]

It turns out that #306 (Gradle 5.6.4) is not enough to use JDK 13, but that Gradle 6 is required (cf. gradle/gradle#10785).

[codecholeric]

Yes, I've noticed that, too. Our path should be to merge #284, then see how we get to Gradle 6 as quickly as possible. Unfortunately we have accumulated some technical dept with respect to the build ☹️