This is just Kotlin. Strongly typed, more concise than Java or Go (and probably Typescript), less likely to blow up at runtime than Typescript, epic tooling, plenty of public code, and a library for basically anything because JVM.
Java runs a Hello World, cold, in a packaged JAR, in about 40ms. What you've seen isn't JVM startup but programs that do a lot at initialisation (like MS Word), as many Java programs like to do (because they often expect to run for a long time, so they don't care about startup time).
