[[kotlin-null-safety]]
= Null-safety

One of Kotlin's key features is {kotlin-docs}/null-safety.html[null-safety],
which cleanly deals with `null` values at compile time rather than bumping into the famous
`NullPointerException` at runtime. This makes applications safer through nullability
declarations and expressing "`value or no value`" semantics without paying the cost of wrappers, such as `Optional`.
Kotlin allows using functional constructs with nullable values. See this
{baeldung-blog}/kotlin-null-safety[comprehensive guide to Kotlin null-safety].

Although Java does not let you express null-safety in its type-system, the Spring Framework
provides xref:core/null-safety.adoc[null-safety of the whole Spring Framework API]
via tooling-friendly https://jspecify.dev/[JSpecify] annotations.

As of Kotlin 2.1, Kotlin enforces strict handling of nullability annotations from `org.jspecify.annotations` package.