![]() The example demonstrates the declaration and use of nullable variables of different types. Unless you need a variable to be null you should specify a non-nullable type, and when you create a. If a variable is declared as a nullable variable, then it can be assigned the null value. Kotlin implements null-safety with its type-system. Type – any basic type of the Kotlin language ( Int, Double, Byte, Short, UByte, Char, String and others). ![]() This is done by adding the symbol ? (question mark) to type name Type? Unlike the Java language (as well as other languages), Kotlin allows the programmer to directly specify nullable types. Declaration of variables that support null-value (nullable-variables). This is a significant advantage of the Kotlin language. That is, the error can be immediately identified and corrected, otherwise the program code will not be compiled. In the Kotlin language, the type system is organized in such a way that errors using nullable types are already detected at compile time. As a consequence, an exception is thrown (in Java it is a ), which is a consequence of the fact that the compiler was unable to detect an error during the compilation of the program. In other programming languages (Java in particular), incorrect use of nullable elements leads to run-time errors, which is very undesirable. When writing programs, it is important to use nullable elements correctly to avoid errors. non-nullable – elements that cannot take a null value.The elvis operator, :, can be used in Kotlin for such a situation. nullable are elements that can take a null value The Elvis operator is a shorthand syntax in Kotlin that provides a concise way of handling null values. Sometimes it is desirable to evaluate a nullable expression in an if-else fashion.Based on this context, Kotlin language elements are divided into two types: In the Kotlin language, null means that there is no value for variables declared as val or var at the moment. The terms null-value and zero-value are different things. This makes applications safer through nullability declarations and expressing value or no value semantics without paying the cost of wrappers, such as Optional. In modern programming languages (including Java, C#, etc.) there are situations when a value does not contain any value. One of Kotlin’s key features is null-safety, which cleanly deals with null values at compile time rather than bumping into the famous NullPointerException at runtime.
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