Comment by t-writescode

I, personally, happen to like writing in Kotlin more than Java - with a lot of experience in both (though admittedly, all? the Java I wrote is in the pre-Streams style).

I like:

  * data class Foo(val theImplementationAndStyleOfDataClasses: String)
  * elvis?.operator?.chaining
  * the order of variable declaration (type afterward)
  * how function pointers at the end of a method call can be auto-inserted as the next curly bracket
  * how you can have fun foo() = returnValue; in one line.
  * fun `method names that can have spaces - and dashes - in them`()

The preceding 3, combined, allow for:

  @Test
  fun `much easier testing`() = commonTestSetupWrapper {
    // the code under test
  }

  * val immutable by default

While I agree that Kotlin has definitely helped push Java in the right direction; and I agree that it's probably not especially necessary to migrate 10MM lines of Java code to Kotlin, especially since they're fully interoperable, I definitely would prefer writing _new_ code in Kotlin over Java for the for-the-lazy devex improvements, if nothing else.

fwiw, my "good at it" programming history follows the lineage in historical order of:

  * Java (8?? years of it including competition programming)
  * C# (5+ years)
  * Python (2016ish to current)
  * Ruby (3-ish years, lots of Rails)
  * Kotlin (2-3 years, through current - written over 40k lines of Kotlin in the last year, alone)