Do creation of Singleton has been changed now? object MySingleton { val num:Int = 10 } No longer create a private constructor

Yep, that is correct

Why this change?

It's an explicit implementation of

Item 3: Enforce the singleton property with a private constructor or an enum type

from Joshua Bloch's Effective Java book. It makes it impossible for the developer to f***-up the definition of a Singleton

I think I misunderstood...I thought there was now a non-private constructor but still is private when trying to call from Java

It's a change coming from Java but this approach has been in Kotlin since before 1.0

I know, I was confused because I don't see a private constructor in the decompiled Java code...but in the bytecode it's there, you're right