[jggonz]

If you're like me and have spent several years working with Java projects, moving to Kotlin will slow you down at first. You also may not know all the cool new features available in Kotlin from day 1, so you may find yourself doing "java" things in Kotlin, or not knowing how to do some things in Kotlin at all.

If you're on a tight deadline for something, you might want to just stick with Java (if you know it) until you can dedicate enough time to learn Kotlin well. If you're new to both Java or Kotlin, then learn both. :)