![]() ![]() In some cases, it’s not necessary to call let() at all. Since our example uses a nullable String, be careful not to accidentally use the extension function CharSequence.map(), which will map each character of the String instead of the String itself. ![]() The map() method allows you to transform an Optional to an Optional of another value. Optional s4 = Optional.ofNullable("Hello") The Kotlin equivalent is straightforward. The ofNullable() method works the same as of(), except that instead of throwing a NullPointerException, a null value produces an empty. In Kotlin, we have to go out of our way to throw the exception. The of() method creates an Optional if a value is present, or forces an immediate NullPointerException otherwise. The Kotlin equivalent of assigning an empty() is to assign a null. Static Optional absent = Optional.empty() To explore all of the possibilities, we’ll assume these constants: static Optional present = Optional.of("Hello") Then we’ll wrap up with a few more thoughts about the trade-offs between using Optional and using Kotlin with nullable types. In this guide, we’ll take a look at how Kotlin’s null-safety features can be used to replace Java 8’s Optional class. ![]() What should you do? Should you leave them as Optional, or change them to more idiomatic Kotlin? When Java 8 introduced Streams for operating on collections of data, it also introduced a similar concept, Optional, which has many methods that are similar to Stream, but operates on a single value that might or might not be present.Īs you migrate your projects from Java to Kotlin, you might come across some Optional objects. ![]()
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