Can be very simple and elegant, like a better Python, on the JVM.
But also very rigorous, as a Java superset, with powerful features like mixing dynamic and static compilation in the same class.
Or even deep, with run-time metaprogramming and compile-time AST manipulation capabilities (giving tools like Gradle, Spock...).
And you have of course multiline interpolated Strings. And so much.
My absolute favorite thing is being able to do something like:
someIntegerCollection = someStringCollection*.toInteger()
canadianUsers = someUserCollection.findAll { user ->
user.countryCode = "CA"
}
canadianUsers = [user for user in someUserCollection if user.countrycode = "CA"]