support Java 11

[mathisdt]

When running ArchUnit 0.9.1 with Java 11, I get the following output:

...
INFO  c.t.archunit.core.importer.JavaClassProcessor      {} Analysing class 'Anonymized$1'
WARN  c.t.archunit.core.importer.ClassFileProcessor      {} Couldn't import class from file:///home/me/workspaces/Default/myproject/target/test-classes/Anonymized$1.class
java.lang.UnsupportedOperationException: null
	at com.tngtech.archunit.thirdparty.org.objectweb.asm.ClassVisitor.visitNestHostExperimental(ClassVisitor.java:158)
	at com.tngtech.archunit.thirdparty.org.objectweb.asm.ClassReader.accept(ClassReader.java:541)
	at com.tngtech.archunit.thirdparty.org.objectweb.asm.ClassReader.accept(ClassReader.java:391)
	at com.tngtech.archunit.core.importer.ClassFileProcessor.process(ClassFileProcessor.java:55)
	at com.tngtech.archunit.core.importer.ClassFileImporter.importLocations(ClassFileImporter.java:317)
	at com.tngtech.archunit.core.importer.ClassFileImporter.importPackages(ClassFileImporter.java:196)
	at com.tngtech.archunit.core.importer.ClassFileImporter.importPackages(ClassFileImporter.java:207)
	at MyTest.<init>(MyTest.java:21)
	...

When running under Java 8, all works fine. It seems that the repackaged version of ASM doesn't support Java 11 - could you please update it or convert it to a real dependency (so I can manage the version)?

[hankem]

As @codecholeric is off for vacation, he might not be able to respond as quickly as usual... ;)

It seems to me that ASM is the most relevant implementation detail of ArchUnit, so it might be difficult to have its version managed externally.

On the jdk-11 branch of my fork, I've tried to update the ASM version to 7.0-beta just released two and a half weeks ago. I'm, however, not yet sure whether there isn't actually more work needed, as 126 of ArchUnit's tests still fail for me with (Open)JDK 11, and I haven't found the time yet to look into the issues in detail.

[hankem]

Okay, 'looking at the issues in detail' boiled down to reading the error message

java.lang.UnsupportedOperationException: This feature requires ASM7
	at org.objectweb.asm.ClassVisitor.visitNestMember(ClassVisitor.java:236) ~[asm-7.0-beta.jar:7.0-beta]
	at org.objectweb.asm.ClassReader.accept(ClassReader.java:651) ~[asm-7.0-beta.jar:7.0-beta]
	at org.objectweb.asm.ClassReader.accept(ClassReader.java:391) ~[asm-7.0-beta.jar:7.0-beta]
	at com.tngtech.archunit.core.importer.ClassFileProcessor.process(ClassFileProcessor.java:55) [classes/:?]

and changing ClassFileProcessor.ASM_API_VERSION from ASM6 to ASM7... ☺

I've just pushed this small change, with which ArchUnit now builds with JDK 11, too.

@mathisdt, unless you want to build that ArchUnit-fork on your own, I'll try to make those artifacts available as version 0.9.2-SNAPHOT.

[mathisdt]

@hankem That would be great! But perhaps the version number could be a bit more stable, e.g. 0.9.1-JAVA11 ?

[hankem]

If the changes work out, I'd like to have them reintegrated via a pull request. After that, there will certainly be a stable release at some point.
Regarding the version number: I think the artifact will not be specific to Java 11, just be able to process its class files. (I've just tested them locally in a Java 8 project.)

[hankem]

I'm sorry for my silence! While I was trying to get access to an "official" repository, I only realized today that I could just as well push the artifacts to github... 😀

But better late than never; you can now get 'com.tngtech.archunit:archunit-junit4:0.9.2-SNAPSHOT' from

    repositories {
        maven { url 'https://raw.github.com/hankem/ArchUnit/artifacts/' }
    }

[hankem]

(You can actually get all of ArchUnit's 0.9.2-SNAPSHOTartifacts from there. I just copy-&-pasted from my example using archunit-junit4...)

[hankem]

I don't know whether @mathisdt had the opportunity to test the snapshot artifacts, but as I'm confident from ArchUnit's tests, I'll open the pull request anyways. ;)

[mathisdt]

@hankem, I didn't have the opportunity to test yet, but I'm also confident in ArchUnit's test coverage.
👍 from my side, thanks for your work!