java.util.function · java.base · since Java 1.8

Predicate

declaration

@FunctionalInterface
public interface Predicate<T>

T → boolean test, the filter shape. Combines logically with and/or/negate — validation rules as data.

Key methods

`boolean test(T t)`	The test.
`default Predicate<T> and(p) / or(p) / negate()`	Boolean algebra over predicates.
`static <T> Predicate<T> not(Predicate<T>)`	Readable negation for method refs (Java 11).
`static <T> Predicate<T> isEqual(Object target)`	Equality test.