```
var s1: String? = null
val s2 = "test"
val s3 ...
# announcementsn
nish
11/05/2017, 2:28 AM Copy code
var s1: String? = null
val s2 = "test"
val s3 = s1 + s2 // output - nulltestnish
11/05/2017, 2:28 AMvar s1: String? = null
val s2 = "test"
val s3 = s1 + s2 // output - nulltest