NichtNullEintrags

NichtNullEintrags is a German term used in software engineering to describe an element of a collection, table, or data structure that is guaranteed to be non-null. The term is not tied to a single standard but is commonly used in German-language documentation to signal a contract: the value of the entry cannot be null at the point of use.

It is often used for map or list entries where a value is required for correct operation, or when an API promises that certain entries satisfy a non-null constraint. In languages with null-safety features, such as Kotlin, a non-null entry is enforced by the type system, so maps declared as Map<K, V> or data objects with non-null properties guarantee that entries do not contain null values.

Implementation can be compile-time, via non-null types and annotations (@NonNull), or runtime, via explicit checks (requireNotNull, Objects.requireNonNull) or validation frameworks, and in databases via NOT NULL constraints. The concept is also applicable to data transfer and serialization, where non-null entries simplify validation and processing downstream.

Non-nullity is a contractual guarantee that may be violated by external input; it does not automatically imply immutability or thread-safety. It is complementary to concepts like Optional, null-safe accessors, and broader data validation practices, and it is often used to reduce the need for repetitive null checks in code paths that rely on reliably present data. See also: Null safety, Optional, NonNull, Nullability.