Scala may be a safer solution because Kotlin is newer, but that doesn't stop Kotlin being a better choice than other older languages like Groovy.
Today the Groovy P.M. announced they're adding statically-typed traits (http://groovy.329449.n5.nabble.com/Adding-Trait-to-Groovy-td...) to Groovy, talking about them like they're an innovation. But they were already implemented by former Groovy++ developer Alex Tkachman (https://code.google.com/p/groovypptest/wiki/Traits) 2 years ago. Groovy added static compilation into Groovy 1 year ago by copying it from Tkachman's Groovy++ codebase, then announced it to the world as "Groovy 2.0" without crediting him. Now they're trying the same trick again, laundering the Groovy++ Traits and passing it all off as "Groovy 2.2".
Alex Tkachman is now one of the Kotlin developers (along with Groovy's creator James Strachan). So which codebase would you trust: one laundered without credit from someone else's implementation (Groovy), or a second try from the actual person who wrote the first attempt (Kotlin)?
Today the Groovy P.M. announced they're adding statically-typed traits (http://groovy.329449.n5.nabble.com/Adding-Trait-to-Groovy-td...) to Groovy, talking about them like they're an innovation. But they were already implemented by former Groovy++ developer Alex Tkachman (https://code.google.com/p/groovypptest/wiki/Traits) 2 years ago. Groovy added static compilation into Groovy 1 year ago by copying it from Tkachman's Groovy++ codebase, then announced it to the world as "Groovy 2.0" without crediting him. Now they're trying the same trick again, laundering the Groovy++ Traits and passing it all off as "Groovy 2.2".
Alex Tkachman is now one of the Kotlin developers (along with Groovy's creator James Strachan). So which codebase would you trust: one laundered without credit from someone else's implementation (Groovy), or a second try from the actual person who wrote the first attempt (Kotlin)?