In fact, we can say that Kotlin is much better than Java code in terms of security, compatibility, type inference, syntax, data classes, boilerplate code, and functional programming . At the same time, there are features similar on both Java and Kotlin, like lambda expressions, type system, and annotation processing.
Read moreShould I learn Java Android or Kotlin?
Conclusion. In general, because of the May 2019 announcement from Google I would recommend beginners at Android app development start with Kotlin however there are some exceptions where I think Java may be better . There are two scenarios I would recommend learning Java first for Android app development as a beginner.
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