Nullness Safety Utilities (nullness package)

Located at dev.anvilcraft.lib.v2.util.nullness, providing non-null/nullable type annotations and corresponding functional interfaces.

Annotations

• @NonnullType – can be used on type parameters to declare non-null (replacement for javax.annotation.Nonnull)
• @NullableType – same as above, for nullable types
• @FieldsAreNonnullByDefault – applied to a package or class, declares fields as non-null by default

Functional Interfaces

Interface	Corresponding Java Type	Description
NonNullSupplier<T>	Supplier<T>	Must not return null
NonNullConsumer<T>	Consumer<T>	Parameter is non-null
NonNullBiConsumer<T,U>	BiConsumer<T,U>	Both parameters are non-null
NonNullFunction<T,R>	Function<T,R>	Parameter and return value are non-null
NonNullBiFunction<T,U,R>	BiFunction<T,U,R>	Parameters and return value are non-null
NonNullUnaryOperator<T>	UnaryOperator<T>	Parameter and return value are non-null

All interfaces support composition (andThen) and a static noop() factory (no-op). NonNullSupplier additionally provides lazy() and of(Supplier) conversion.

Import Paths Across Versions

Since module.util was not released as a standalone module in some versions, the import path for the nullness package varies by version:

Version Range	Import Path
1.21.1	import dev.anvilcraft.lib.v2.util.nullness.NonNullSupplier;
1.21.2–1.21.11	import dev.anvilcraft.lib.v2.registrum.util.nullness.NonNullSupplier;
26.1	import dev.anvilcraft.lib.v2.util.nullness.NonNullSupplier; (restored)

In versions 1.21.2–1.21.11, module.util was not synchronized due to capacity constraints. The nullness functional interfaces were embedded into module.registrum to ensure Registrum could compile independently. In 26.1, module.util synchronization was restored and the import path returned to its original location.

Deprecated Interfaces

• NullableSupplier<T> – please use Supplier<T> directly annotated with @Nullable.