To prevent unwanted modifications, obtain read-only views of mutable lists by casting them to List. Creating Kotlin Listsįor list creation, use the standard library functions listOf() for read-only lists and mutableListOf() for mutable lists. Kotlin mutable or immutable lists can have duplicate elements. The elements of list can be accessed using indices. A Kotlin list can be either mutable ( mutableListOf) or read-only ( listOf).

If the library is reasonably popular, it is very likely that there is already a Kotlin alternative or companion library that will help you.Kotlin list is an ordered collection of items. However, you are probably not the first to have this happen. Java libraries can sometimes cause problems in Kotlin.

The individual commits show the original code with the failed test, the fix with the alternate matcher, and the final mock setup in Kotlin syntax. You can check the full code in my GitHub repository. In order for this code to compile, you need to add the following imports: import org. The method I was trying to stub was expecting a non-null String as an argument: interface MyDependency doReturn 'Hello, World!' The cause was the any() argument matcher in my code to set up the method stub: val myDependencyMock = Mockito. When I ran the test, it failed with a NullPointerException: I recently ran into such a problem when trying to mock a dependency with Mockito. Unfortunately, it can sometimes cause problems when interacting with Java code or libraries. The null safety feature in Kotlin is great for preventing NullPointerExceptions that are thrown at runtime.

Any kotlin