If you are a BE developer using Java or an Android dev who want to write BE and if you know kotlin, that's a breeze. Here is Matt thorfiled helping us understand the same. Matt is the author of Spring Boot Application using Kotlin course on LinkedIn Learning. https://medium.com/androidiots/androidiots-podcast-15-using-kotlin-as-a-backend-language-with-matt-3f8f0aa78b00

Nice podcast, but why would you say that Kotlin is slower than Java by fractions of a second because of null checks without any benchmarking? Why?

I think it was a fair explanation of the minor overhead Kotlin brings and the null checks were a good example of this, and one which is simple to explain on a podcast format.

These benchmarks are good, they show that some constructs are slower than the other. While Matt basically said that any Kotlin code is slower than Java as you will find null checks in bytecode for almost any Kotlin code. Long time ago I saw benchmark showing that Kotlin with these null checks is even tiny bit faster (within error range) than Java. JWM JIT is pretty good in optimizations. But even if we assume that null checks makes Kotlin slower, what does fractions of a second mean? Is it 0.1s or 0.0000001s per each check? The last one looks more like a truth so does it even make sense to mention it?

Yeah I see what you mean - it's a hard question to answer (especially on a podcast interview!) because there is a difference but it's not something the majority of application developers need to concern ourselves with (and if you did you probably wouldn't be using Java, but a systems language instead e.g. C, Rust)