Kotlin didn't invent type inference, it's a feature from ML.

And not only that, Java was like 40 years late to the party. ML had Hindley-Milner type inference back in 1978! I can only imagine how foreign ML must have felt compared to other languages at the time.

I never said Kotlin invented type inference, just that the syntax was straight adopted from kotlin

What syntax? val and var were used by Scala before Kotlin. Lombok also has val. Java just needed to pick a keyword.