Kotlin fixes just trivial things - like nullability for example. Java still doesn't have a good solution, only about 5 bad ones and nothing is in sight. It even looks like Java designers simply don't consider it a problem anymore ...

Instead, they focus on things like value types. Which are definitely cool, but they don't actually solve any of my problems. Typical business apps written in Java don't suffer from performance issues, they suffer from (accidental) complexity explosion and subsequent buginess (of which NPEs is a symptom).