JRuby support

[headius]

This imports the JRuby code for io/wait, with tests green (see caveat) and hooked up to CI.

One test is skipped on JRuby due to jruby/jruby#6852, which will be fixed in JRuby 9.3.1.0.

This support is needed to release a JRuby-specific io-wait gem, a dependency of net-protocol. Without JRuby support in this gem we can't use any of the other net* gems.

[headius]

I have no idea why the JRuby jobs are stuck.

[headius]

I have pushed the missing bits for JRuby and rebased on current master.

Additional changes from previous review:

• Rakefile tweaks to get paths set properly for JRuby, with the JRuby-specific wait.rb moved under ext/java/lib.
• Gemspec tweaks to include lib/io/wait.jar and the Java ext files in the gem

This addresses both of @ahorek's review comments. I also tested that the built gem can install and replace the builtin io/wait in JRuby.

So it is pretty close now.

[headius]

Something is still not right with the JRuby builds.

[olleolleolle]

is it missing a bundle exec before rake?

[headius]

There are no dependencies for CRuby (dev or otherwise) so no bundling is done in any of the builds.

I will add the necessary bits for JRuby.

[headius]

Looks like we have a winner!

This can be squashed during merge, or if preferred I can rewrite the commits to better reflect the changes I made.

[headius]

Pinging maintainers... I believe this is ready to merge and is necessary for JRuby 9.4 to source io-wait (and the net/* libraries that use it) from the gems. High priority for JRuby 9.4 release in the next month or two.

[headius]

I have updated this from master again. Is there anything else needed to merge?

[headius]

The omitted test has been un-omitted, since that issue was fixed in JRuby 9.3.1.0 (current is 9.3.3.0).

[headius]

I rebased this on master and it will merge now. I'm fine with merge commit or squashed.

[nobu]

These lines seem unnecessary.

[headius]

I have addressed all review comments.

[hsbt]

🎉

[headius]

Thank you both!