actually I'm still unsure about kotlin. some things are really great some things are not. I mean i will still use kotlin, especially for libraries since it is great for that. however somehow I still missed something on top of Executors and CompletionStage. And I'm totally unhappy about "So, why doesn’t Kotlin have its own package manager, or its own build system? Because there’s already Maven and Gradle, and re-using their huge number of plugins is crucial for many projects."
The answer would be totally valid, however people who worked with maven, gradle, ant or even sbt (which isn't offically supported) could be unhappy. all of these build systems are useful, but not actually great. I mean you could work with them but it's not actually great to use them.
Maven is fantastic in my book. Literally the best build system I've seen. But even if you disagree with me on the specifics, if there's something you want to change about one of those tools, surely you'd want to make the same change when building Java? I don't see any value in rewriting one of those tools in Kotlin to make it Kotlin. (And if some particular idea is easier to express in Kotlin, I've written Maven plugins in Scala, I'm sure you could do it in Kotlin too)
how do you do conditionals or loops in maven?
You can use the maven polyglot plugin [1] to write your POM in something other than XML. It's fairly new, but it's there. We use it in JRuby to write our POMs in Ruby. As an example of a loop:
https://github.com/jruby/jruby/blob/8e29ae1302e7aa989b8808f7...