![]() ![]() You can use it in combination with the Elvis operator. So if youre wrong, you get a null pointer exception. ![]() If a variable can be null, it's not safe to call a method on the variable because this can cause a NullPointerException. It is a way to indicate which variables can possibly hold a null value. 1.0 fun CharSequence. Note that if the variable is a mutable property, you won't be able to smart cast it to its non-nullable type inside the if statement (because the value might have been modified by another thread) and you'd have to use the safe call operator with let instead. Kotlin will then access the value without further safety checks. The most important difference between Kotlin's and Java's type systems is Kotlin's explicit support for nullable types. Variable that cannot be null var str: String K. One of Kotlins key features is null-safety, which cleanly deals with null values at compile time rather than bumping into the famous NullPointerException. Therefore when comparing to null, the structural equality a = null is translated to a referential equality a = null.Īccording to the docs, there is no point in optimizing your code, so you can use a = null and a != null For example, a non-null string will be written String and a nullable one will be String. ![]() A structural equality a = b is translated to a?.equals(b) ?: (b = null) ![]()
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