The following code shows up "Property must be initialized or be abstract" error.I understand that I can use lateinit in such cases but I wanted to know the reason behind the restriction .

class Student{
  val s:String 
}

CodePudding user response：

In the case of a non-nullable property like in your example, the reason is necessity. Java implicitly gives member variables a value of null. In Kotlin, a non-nullable property cannot have a value of null, so you have to give it an instance of something to be the starting value.

But even if you declared it as nullable String?, Kotlin will require you to specify the starting value. Kotlin avoids making implicit assumptions about the intent of your code. Kotlin's design goals are to make code more readable and robust. The designers have done research on common causes of bugs in other languages, and have made Kotlin more restrictive in areas that have been frequent sources.