Java and Kotlin
Though I haven't been coding any Java since quite some time, I have been following its development from the side. Depending on the level of maturity the technology used by an organisation has reached, Java can become the leading technology. Though maintenance and scalability are no match against languages like Elixir and Ruby, the robustness and maturity of the language, its ecosystem, its libraries, is ofcourse years ahead.
With Google's engagement to push Kotlin for Android development, Java became new relevance in the domain of mobile applications. Kotlin's approach is different from Java, being functional, yet using the JVM allows it to use the full power of the Java language natively.