> Grails (built on spring boot) won't support anything higher than Java 8 until end of 2018.
Grails 3 is built on Boot but virtually no-one uses it. Websites using Grails have largely remained with version 2 and no-one's starting new projects in version 3, so I doubt the Grails backers will even bother to add Java 9+ support to Grails 3.
The Apache Groovy backers also seem to have given up on releasing a version 3. A few months ago, they pulled preview support for version 3 features from the upcoming Groovy 2.6. Since then, Groovy 3 has been stuck on permanent alpha version, with no-one in their project management committee showing any interest in moving it forward.
Grails 3 is built on Boot but virtually no-one uses it. Websites using Grails have largely remained with version 2 and no-one's starting new projects in version 3, so I doubt the Grails backers will even bother to add Java 9+ support to Grails 3.
The Apache Groovy backers also seem to have given up on releasing a version 3. A few months ago, they pulled preview support for version 3 features from the upcoming Groovy 2.6. Since then, Groovy 3 has been stuck on permanent alpha version, with no-one in their project management committee showing any interest in moving it forward.