Java 8 Upgrade

This page summarizes currently known problems when running with java8, latest beta (1.8.0-ea-b119).

see also MNG-5551 for compilations issues

Related continuous integration job is https://builds.apache.org/view/M-R/view/Maven/ Interesting is that is takes about 3 times the amount of time to execute the job with JDK8 compared to JDK7 !  

maven-verifier

embedded mode does not work due to sun bug 9009028 - System.setProperties(null) corrupts java.home, turned into JDK-8030781. This affects at least maven-core and surefire.

maven-shade-plugin

Believed to have substantial problems due to ASM 5 being required. ASM5 has a tentative release date in march, with a current beta version and possibly another beta later.

maven-compiler-plugin

The current compiler plugin should work on java8, as long as you stay away from the error-prone compiler. The compiler plugin IT's fail on JDK8 because the error-prone-compiler does not work with JDK8. plexus-compiler has adaptations for error-prone on branch MCOMPILER217, but error prone IT fails on m-c-p. https://code.google.com/p/error-prone/issues/detail?id=224

maven-surefire-plugin

Running forkMode=never was fixed in 2.17 (unreleased as of yet). Building surefire on jdk8 requires using the -Dverifier.forkMode=once option (due to maven-verifier embedded mode issue).

maven-javadoc-plugin

The javadoc executable has become stricter compared to previous versions:

• "unknown tag" has become an error
• "reference not found" has become an error

This means that generating the javadocs can suddenly fail only by upgrading the JDK

See https://jira.codehaus.org/browse/MSITE-701 for the details.

Another issue is that the excludedocfilessubdir option is ignored with Windows7, org.apache.maven.plugin.javadoc.JavadocReportTest.testJavadocResources() fails when trying to confirm that the maven-feather.png hasn't been copied (watch it, it's the third assertion for the feather!)