It's remarkably uncool to like Java, but I know what you mean. I did a web app using Play! version 1 and it was a really enjoyable experience, even though it was in Java. Also, Android development is not brilliant, but most of that is the emulator's slowness, not the Java language itself.

Also I love IntelliJ or Netbeans both a lot more than Eclipse.

I'm sure there is a Java dev experience that is pretty great, especially if you can pull in some of the functional things from Java 8 and maybe immutable things from guava. I haven't tried that.

I have tried Kotlin and I enjoyed playing with it in IntelliJ, though I haven't done anything beyond project euler problems and some JUnit testing.