Kotlin is the first language I've gotten excited about in a long time. It's close enough to Java that I can get my engineers up to speed in a few hours, but it removed a lot of the bloat and tedium.

The JNV / JS / Native targets are also really promising, though I haven't played around with them much. The JS and Native runtimes are a bit limited since they don't include the Java standard library, from what I can tell.