Java reduce but with interface

.java

package org.example;

import java.util.List;
import java.util.stream.Stream;

interface StringFilter {
    List<String> filter(List<String> people);

    default StringFilter and(StringFilter second) {
        return list -> second.filter(this.filter(list));
    }
}

public class App {
    public static void main(String[] args){
        StringFilter a = people -> people.stream().filter(s -> !s.equals("a")).toList();
        StringFilter b = people -> people.stream().filter(s -> !s.equals("b")).toList();
        StringFilter c = people -> people.stream().filter(s -> !s.equals("c")).toList();
//        StringFilter d = people -> people.stream().filter(s -> !s.equals("d")).toList();


        List<String> result = Stream.of(a, b, c)
                .reduce(StringFilter::and).get().filter(List.of("start", "a", "aa", "b", "bb", "c", "cc", "d", "dd"));

        System.out.println(result);
    }
}

Stdout: [start, aa, bb, cc, d, dd]