Lines 8–11: We add four elements to the list, using the add method. Since the list is empty, null is returned. Line 5: We use the lastOrNull method to get the last element of the list. This list contains no elements at this point. This is because the value passed to the lambda inside the let method will not change even if the original variables changes its value that will make your block much safer in this particular case.Line 3: We create a new ArrayList object with the name list. It’s also worth mentioning that if you are working with mutable variables (something I would NOT recommend), using let is safer than using an if condition. That looks concise and clean there could be some arguments against it due to not being “human-readable” but I can promise that once you get used to the use of safe calls and let methods you’ll read it clearly with no effort. If we take the example we used in our last Kotlin article about Either: fun findEmployeeByName(name: String): Either ') Not always, we might have a findEmployee method in our service where we want to express the possibility of not finding the employee by using a nullable type. That’s definitely the best way to avoid having to deal with nulls in our language, although is this always possible? This is the way that they decided to achieve null-safety in Kotlin.

Non-Nullable Types in Kotlinīy default Kotlin types are not nullable, what means that it’s impossible to assign null to them. Kotlin provides different mechanisms to help solve this problem.

In this article you will learn how to handle nullable types in Kotlin correctly. Having to place null check conditions everywhere just to make our code null-safe is something that probably most of us have suffered quite often. One of the most annoying aspects in writing code in Java is dealing with null elements.

Null in kotlin