code: public static <T> Collector<T, ?, Boolean> allMatch(Predicate<? super T> predicate) {
          return Collector.of(
              () -> new Boolean[1],
              (a, t) -> {
                  if (a[0] == null)
                      a[0] = predicate.test(t);
                  else
                      a[0] = a[0] && predicate.test(t);
              },
              (a1, a2) -> {
                  a1[0] = a1[0] && a2[0];
                  return a1;
              },
              a -> a[0] == null || a[0]
          );
      }
docs: Get a {@link Collector} that calculates the <code>ALL()</code> function.