This bug will track the process of using the new gemiified stdlib gems for Ruby 2.5 (which should be released as JRuby 9.3 or JRuby 10).

The current Appveyor builds show the gems being installed. https://ci.appveyor.com/project/MSP-Greg/appveyor-ruby

Many of the libraries in question either do not have (never had) JRuby equivalents (sdbm etc) or are unmodified (or barely modified) pure-Ruby libraries. Others like openssl will need to have a -java equivalent so users don't have to isolate those dependencies.