Jigsaw support

[lpandzic]

There was some talk about jigsaw support on google group but I'd like to formalize it as a feature request in this issue.

[lpandzic]

I've managed to modularize and build jackson-databind, jackson-core and jackson-annotations with jdk9 and also successfully tested integration against an example module which uses jackson-databind module.
There are some rough edges that require further research but I believe this is doable, even with Java 7 as a target (so those jars can behave both as regular jars and modules, depending on the runtime and whether on classpath or module path).

[cowtowncoder]

Would this require more substantial changes than, say, support for OSGi modules (which only needed Maven build support)?

[lpandzic]

FasterXML/jackson-core#358
FasterXML/jackson-annotations#117
The only issue I have right now is compiling source to JDK 7 target. New release flag doesn't seem to work with maven compiler plugin.

I'll add jackson-databind one tommorow.
Update: it won't build on travis as there's no jdk with jigsaw yet. (oraclejdk9 doesn't include jigsaw)

[lpandzic]

I've added some comments to FasterXML/jackson-annotations#117 which apply to all 3 PR's.
There are 2 issues remaining:

• Travis doesn't support JDK9 EA with Jigaw - Add support for JDK 9 EA with Jigsaw travis-ci/travis-ci#7397
• backwards compatibility build.

[cowtowncoder]

Ok thank you. Apologies for slow follow-up; just released 2.9.0.pr1 and trying to go through bug backlog.

[cowtowncoder]

As per discussion on annotations, core, I don't think this can be done before JDK 9 is required.
But at very least would wait until Java 8, which is for Jackson 3.0; flagging as such for now.

[lpandzic]

Hello, sorry for long delay. It should be doable on Java 7 but I'd also wait for 3.0.0 and Java 8 before doing this.

[cowtowncoder]

Closing since there's also #1542