In Kotlin:

String

can never be null,

String?

can. In Java

String

does not express any notion of whether or not it can be null.

I thought its something related to generics

So, in your example with the

anyKotlin

method, if the compiler infers

String

for

T

, it assumes "hey this method cannot return null now!". And since

anyKotlin

is written in Kotlin, the compiler "trusts" it (not sure of the exact rules here). Inside

anyKotlin

, the compiler cannot insert any null checks after the Java method returns, since it does not know what

T

actually is,

T

might be

String?

in Kotlin, which then means that it can be null, so a null check would not be correct. So there cannot be any checks here.

thank you again for explaining it 🙂