Should I learn Kotlin or stick to Java?

Google announced Kotlin as an official language for Android development. Some famous developer companies, like square, started using kotlin as their production language long before the official announcement was made.

Now one of the most trending questions juggling around the minds of many experts and most beginners is should I learn kotlin or stick to java? Here’s some point should be made based on three stages of a developers like really really beginner, ninja apprentice, totally ninja.