Add support for Java 17-EA

[garydgregory]

Running Maven on a Java 17-EA project on GitHub throws an exception rooted with the cause Unsupported class file major version 61:

java.lang.instrument.IllegalClassFormatException: Error while instrumenting sun/util/resources/cldr/provider/CLDRLocaleDataMetaInfo.
	at org.jacoco.agent.rt.internal_f3994fa.CoverageTransformer.transform(CoverageTransformer.java:94)
	at java.instrument/java.lang.instrument.ClassFileTransformer.transform(ClassFileTransformer.java:244)
	at java.instrument/sun.instrument.TransformerManager.transform(TransformerManager.java:188)
	at java.instrument/sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:565)
	at java.base/java.lang.ClassLoader.defineClass2(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1101)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:182)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:814)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:735)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClass(BuiltinClassLoader.java:616)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:631)
	at java.base/java.lang.Class.forName(Class.java:543)
	at java.base/java.util.ServiceLoader.loadProvider(ServiceLoader.java:852)
	at java.base/java.util.ServiceLoader$ModuleServicesLookupIterator.hasNext(ServiceLoader.java:1076)
	at java.base/java.util.ServiceLoader$2.hasNext(ServiceLoader.java:1299)
	at java.base/java.util.ServiceLoader$3.hasNext(ServiceLoader.java:1383)
	at java.base/sun.util.cldr.CLDRLocaleProviderAdapter$1.run(CLDRLocaleProviderAdapter.java:89)
	at java.base/sun.util.cldr.CLDRLocaleProviderAdapter$1.run(CLDRLocaleProviderAdapter.java:86)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:554)
	at java.base/sun.util.cldr.CLDRLocaleProviderAdapter.<init>(CLDRLocaleProviderAdapter.java:86)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:78)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
	at java.base/sun.util.locale.provider.LocaleProviderAdapter.forType(LocaleProviderAdapter.java:188)
	at java.base/sun.util.locale.provider.LocaleProviderAdapter.findAdapter(LocaleProviderAdapter.java:287)
	at java.base/sun.util.locale.provider.LocaleProviderAdapter.getAdapter(LocaleProviderAdapter.java:258)
	at java.base/java.text.DecimalFormatSymbols.getInstance(DecimalFormatSymbols.java:180)
	at java.base/java.util.Formatter.getZero(Formatter.java:2453)
	at java.base/java.util.Formatter.<init>(Formatter.java:1972)
	at java.base/java.util.Formatter.<init>(Formatter.java:1994)
	at java.base/java.lang.String.format(String.java:3290)
	at org.junit.platform.engine.UniqueIdFormat.<init>(UniqueIdFormat.java:74)
	at org.junit.platform.engine.UniqueIdFormat.<clinit>(UniqueIdFormat.java:42)
	at org.junit.platform.engine.UniqueId.root(UniqueId.java:80)
	at org.junit.platform.engine.UniqueId.forEngine(UniqueId.java:68)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discoverEngineRoot(EngineDiscoveryOrchestrator.java:100)
	at org.junit.platform.launcher.core.EngineDiscoveryOrchestrator.discover(EngineDiscoveryOrchestrator.java:85)
	at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:92)
	at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:67)
	at org.apache.maven.surefire.junitplatform.TestPlanScannerFilter.accept(TestPlanScannerFilter.java:56)
	at org.apache.maven.surefire.api.util.DefaultScanResult.applyFilter(DefaultScanResult.java:102)
	at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.scanClasspath(JUnitPlatformProvider.java:147)
	at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.invoke(JUnitPlatformProvider.java:128)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:428)
	at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:162)
	at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:562)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:548)
Caused by: java.io.IOException: Error while instrumenting sun/util/resources/cldr/provider/CLDRLocaleDataMetaInfo.
	at org.jacoco.agent.rt.internal_f3994fa.core.instr.Instrumenter.instrumentError(Instrumenter.java:160)
	at org.jacoco.agent.rt.internal_f3994fa.core.instr.Instrumenter.instrument(Instrumenter.java:110)
	at org.jacoco.agent.rt.internal_f3994fa.CoverageTransformer.transform(CoverageTransformer.java:92)
	... 48 more
Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 61
	at org.jacoco.agent.rt.internal_f3994fa.asm.ClassReader.<init>(ClassReader.java:196)
	at org.jacoco.agent.rt.internal_f3994fa.asm.ClassReader.<init>(ClassReader.java:177)
	at org.jacoco.agent.rt.internal_f3994fa.asm.ClassReader.<init>(ClassReader.java:163)
	at org.jacoco.agent.rt.internal_f3994fa.core.internal.instr.InstrSupport.classReaderFor(InstrSupport.java:280)
	at org.jacoco.agent.rt.internal_f3994fa.core.instr.Instrumenter.instrument(Instrumenter.java:76)
	at org.jacoco.agent.rt.internal_f3994fa.core.instr.Instrumenter.instrument(Instrumenter.java:108)
	... 49 more

For example, our build at Apache Commons BCEL: https://github.com/apache/commons-bcel/runs/1623906918?check_suite_focus=true

TY!

[marchof]

This is already implemented in #1132 but not yet released.

See change log: https://www.jacoco.org/jacoco/trunk/doc/changes.html

You can try the current snapshot version from our snapshot repo: https://www.jacoco.org/jacoco/trunk/doc/repo.html

[garydgregory]

Thanks for the info @marchof

[DJViking]

This is already implemented in #1132 but not yet released.

See change log: https://www.jacoco.org/jacoco/trunk/doc/changes.html

You can try the current snapshot version from our snapshot repo: https://www.jacoco.org/jacoco/trunk/doc/repo.html

When will there be a final non-experimental implementation?
Now that Java 17 has been released.

[garydgregory]

And Java 18-EA 😉

[Godin]

When will there be a final non-experimental implementation?

see https://www.jacoco.org/jacoco/trunk/doc/faq.html

When will feature X be released?

JaCoCo is maintained by volunteers in their free time. Since we cannot guarantee free capacity, we do not commit to particular release dates. Typically, you can expect a couple of releases every year.

In the change log, you can see all features that have been implemented in master branch and will be available with the next release. And in the meantime you can test latest build of master branch (Maven SNAPSHOT) and provide feedback to us.

---

Also as far as our testing shows
despite word "experimental" in released JaCoCo version 0.8.7,
you won't notice any differences in behaviour with unreleased 0.8.8 in regards of Java 17 class files - see https://twitter.com/_godin_/status/1438922086899126278