From the announcement blog post:
Our vision for Kotlin is to enable the use of a single expressive, performant, strongly typed language across all components of a modern application. Kotlin 1.1 makes two major steps towards this goal.
Second, we’re introducing support for coroutines. As a lightweight alternative to threads, coroutines enable much more scalable application backends, supporting massive workloads on a single JVM instance. In addition to that, coroutines are a very expressive tool for implementing asynchronous behavior, which is important for building responsive user interfaces on all platforms.
Below we describe these two changes further. In other news: we’ve added type aliases, bound callable references, destructuring in lambdas and more. See the details in our What’s new page (check out the runnable examples!).
Kotlin is available as a plugin for IntelliJ IDEA, NetBeans and Eclipse.