Kotlin
Kotlin has gained popularity after it is being supported by Google and is adopted as a first-class Android development language. Kotlin has many useful features and is expressive which makes it a great alternative for Java. JetBrains has made the language fault-proof which is easier to maintain. Kotlin can also be used for JVM development using Java frameworks. Also, JetBrains is working on the Kotlin multi-platform that will allow you to develop multi-platform applications with shared codebases.