anyMatch, allMatch and noneMatch

Key points

• All three take a Predicate and return a plain boolean. They are terminal ops, so the pipeline runs.
• anyMatch stops at the first true. allMatch and noneMatch stop at the first counter-example.
• On an empty stream allMatch is true and anyMatch is false. That is vacuous truth, not a bug.
• noneMatch(p) always agrees with allMatch(p.negate()). Pick whichever one reads like the sentence in the ticket.
• Want the element itself, not a yes or no? Use filter(...).findFirst() instead.

Example

import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<Integer> nums = List.of(3, 8, 5, 12, 7);

        System.out.println("anyMatch  > 10 : " + nums.stream().anyMatch(n -> n > 10));
        System.out.println("allMatch  odd  : " + nums.stream().allMatch(n -> n % 2 == 1));
        System.out.println("noneMatch < 0  : " + nums.stream().noneMatch(n -> n < 0));

        // Short-circuit proof: anyMatch stops at the first true.
        System.out.println("-- anyMatch walk --");
        boolean hit = nums.stream()
                .peek(n -> System.out.println("  testing " + n))
                .anyMatch(n -> n > 4);
        System.out.println("found          : " + hit + "  (12 and 7 were never tested)");

        // Empty stream: allMatch is true, anyMatch is false. That is vacuous truth.
        List<Integer> empty = List.of();
        System.out.println("empty allMatch : " + empty.stream().allMatch(n -> n > 100));
        System.out.println("empty anyMatch : " + empty.stream().anyMatch(n -> n > 100));

        // noneMatch(p) is the same answer as allMatch(negated p).
        System.out.println("agree          : "
                + (nums.stream().noneMatch(n -> n > 20) == nums.stream().allMatch(n -> n <= 20)));
    }
}

The match family answers the question and then stops reading.